As the sense of feeling has been at once manifested in the vegetative

animals as a peripheric nervous sense; so antithetically or _vice

versâ_ it is in the higher animals the light-sense, as being the

central nervose sense, which appears.

3341. Hitherto both these senses stood altogether alone with each other

upon the stage of animal existence, in order, as it were, to play

their parts in mutual consent; but so soon as the sense of feeling

became individualized into tactile organs, then also the eye made its

appearance in a detached or isolated manner.

3342. The Fish's eye is upon the whole composed of the same structures

as in the Mammalia; but it is devoid of motion and external coverings.

3343. The ear, as being the sense of motion, has scarcely withdrawn

itself from the brain, has not yet become a true external organ, and

that portion of it which appears externally, is subservient to inferior

systems, such as the branchiæ or gills.

3344. The external auditory organ has become confluent with the

branchial aperture, and the auditory ossicles have become parts of the

branchial operculum.

3345. In the internal ear only the three semicircular canals have been

left. The cochlea is not yet developed.

As true palpebræ or eyelids are wanting to the visual organ, so also

are the conchs of the external ear.

3346. The nostrils exist, because a vertebral canal, which terminates

in them, is present; stoutly-developed olfactory nerves are also

present, so that the sense of smell cannot be wanting. Only this sense

has not yet taken the respiratory organ into communication with itself,

and both therefore live for themselves in an arrested or stunted

condition. This nasal organ does not open into the mouth, admits of

neither water nor air passing through it, and therefore serves not as

a test-organ to the respiratory process. This is my main point for

distinction of Fishes from Reptiles.

3347. Every Sarcozoon, whose nostrils do not open into the mouth, is a

Fish. The Siren therefore does not belong to the present class, while

the Lepidosiren, having an imperforate nasal organ, does.

3348. The tongue has remained rather an organ of touch and deglutition,

than an instrument of taste. The salivary glands are scarcely developed.

3349. But the tongue here appears _for the first time_ in the animal

kingdom as a perfect organ provided with muscles, and a lingual bone,

as in Man; Fishes are, as regards the development of this sense the

_Glossozoa_, Lingual or Tongue-animals.

3350. As Fishes are the repetition of the intestine and vitellus, so

they may be termed _abdominal_ or rather _Pelvic animals_. They are an

abdomen, unto which are appended branchiæ, fins and head.

They are the repetition of the Infusoria, Mussels, and Worms; in them

we meet with mucus, branchial opercula, articulated filaments, and

labial cirrhi or palpal organs.

_Class 11. Myozoa, Rhinozoa._

3351. Those Sarcozoa which for the first time obtain true muscles and a

perforated nasal organ are the _Reptilia_.

3352. True muscles are red, have a definitely circumscribed outline,

and are divisible into head, fleshy portion or belly, and tail or

tendon. As such they are found for the first time in Reptiles.

_Thorax._

3353. With the osseous system in Fishes the sexual abdomen was chiefly

developed; with the muscular system therefore, as in the present class,

the abdomen proper or intestinal abdomen becomes perfectly developed,

and the thorax more spacious in calibre.

3354. The thorax is still blended with the abdomen. In Fishes the

disposition was already stirring to create for themselves an air-organ;

only this was imperfectly attained, since the swim-cyst communicated

with the gullet, but not with the branchial arches or larynx, nor with

the nasal organ, as in the present class.

3355. Now, if the swim-cyst be symmetrically developed, if it

communicates with the branchial larynx and opens through the nose, the

aerial respiration is completely attained, and shares its dominion over

the body along with the digestive function.

3356. A Fish, respiring through the nose into two swim-bladders, is an

Amphibious animal, a _Reptile_.

3357. In the Reptile, however, the thorax is still subordinated to the

abdomen. Its lungs traverse the whole abdominal cavity, and its manner

of breathing is still similar in character to the abdominal function.

The lungs are simply two membranous bladders, like two intestines, and

admit also of being voluntarily filled with air like the intestine is

with water. This filling or inflation of the Reptile's lungs takes

place also by the abdomen being expanded at the same time that the

mouth is closed by the muscles of the fauces, and is therefore a true

process of deglutition.

3358. Their inspiration is still therefore fish-like in character,

excepting that the air is drawn in by the nostrils; the respiratory

process, however, and the respiratory organ is constituted as in the

perfect air-breathing animals.

3359. Reptiles may therefore be called _Abdominal animals_, while the

Fishes are Pelvic animals.

3360. The metamorphosis of the branchial arches into larynx is placed

beyond doubt in the Reptiles. The anterior branchial arches frequently

unite with the lingual bone, whereby the latter obtains several cornua.

3361. The thyroid gland also makes its appearance here for the first

time, while the branchial vessels separate from the arches. Fishes have

therefore no thyroid gland.

3362. The circulation is complete. The venous and also the arterial

blood enters the heart. But both kinds of blood are still mingled

with each other as in Fishes. Yet already, through the direction and

arrangement of the cardiac orifices, provision seems to be made for

their separation.

3363. The rationale of this mixture of the blood appears to reside in

the fact, that many of these animals, and probably all of them in the

ovum state, breathe by branchiæ. (This proposition, which was announced

in the 1st Edition, 1810. § 305, and there based upon the transitional

stages traversed by the animal classes during embryonic development,

has since then been raised to a state of certainty.)

3364. The mixture of the blood takes place through an opening in the

septum separating the two cardiac ventricles, and which corresponds to

the foramen ovale of the foetus. The heart of Reptiles is therefore a

persistent foetal heart.

3365. Without doubt, however, the arterial blood only enters the left

heart, while the venous remains in the right, to be thence driven into

the lungs.

3366. In other respects the foramen ovale is not a true opening, but

a bifurcation of the vena cava, one branch of which passes into the

right, the other into the left ventricle, as I have demonstrated in the

'Beyträgen zur Anatomie' (Frankfurt bei Wesche), in treating of the

calf's heart.

3367. There are generally no foramina in the body, but only fissures

without orifices.

_Abdomen._

3368. The digestive organs are pretty similar to those in Fishes, as is

exemplified by the intestine, liver, and spleen; the digestive process

is, however, more energetic, and frequently aided by venom or poison.

3369. The sexual parts are perfect. The first true testes and ovaria

have originated. The tegumental formation has consequently passed

over at the extremities into a glandular, because the vascular system

preponderates. Even in the highest Fishes, such as the Rays and Sharks,

the testes and ovaria are still not developed to the extent which they

are in Reptiles.

3370. In the female the oviducts pass together as complete cornua into

an uterus. In the male the seminal ducts are still indeed separate,

yet the two bodies or crura of the penis are frequently developed, and

continue separate in the Serpents and Lizards, but are connate in the

Tortoises.

3371. The kidneys are distinct and symmetrical; their ureters usually

unite into a large urinary cyst. Thus, the sexual lung is also

significantly developed.

3372. Many of these urinary bladders split, as in the Tortoises, into

two cornua. This is the form under which the cyst again occurs in

Birds, where its two cornua have been incorrectly termed coeca, but

the urinary cyst rectum, because the intestine opens into it.

3373. In Reptiles also there is a cloaca or sexual orifice, into which

all the sexual apertures meet together.

The ova of Reptiles possess a vitellus and albumen, and are surrounded

by a membranous or sometimes by a calcareous shell.

3374. Hence Reptiles have originally also a coecum, but it has for

the most part disappeared; like its antetype the vitelline canal, which

is so small in most Fishes and Birds, as to be scarcely distinguishable.

The tail projects from the body, and is rather trailed after the

animal, than enabled to assist the body in its motions, as in Fishes.

_Senses._

3375. Many Fishes have only a vertebral column without lateral bones;

in the Thoracic animals this deficiency can hardly occur any longer,

although we are not, on the other hand, to expect any great amount

of perfection to be attained by these parts. Reptiles have osseous

ramules, whether such be ribs or true feet; the Serpents have indeed

only ribs, but these exist in great numbers; in the Frogs, on the

contrary, ribs are wanting, but they have limbs.

In no Reptile do fin-rays occur; consequently, there are no peculiar

bones as in Fishes.

3376. In Reptiles the limbs themselves are in a varied or undetermined

state, although they constitute a class in which the formation of true

muscular limbs is decided. In Reptiles the toes appear for the first

time.

3377. As regards the tegument, it quite corresponds with that of the

Corals, Snails, and Crabs, of which the Reptiles are a repetition. In

some cases it is slimy and naked; in others Mussel-shells originate,

as in the carapace of the Tortoises; the scales, scutes, and claws of

Serpents and Lizards repeat the rings and scutes of Crabs.

3378. The head has separated itself more from the thorax, the eyes and

ears being much more perfect; as regards the latter organs the cranium

is always perforated, in the former there are eyelids.

3379. The eyes have still no power of free motion, and the eyelids are

as yet very imperfect. It is principally the lower eyelid which closes,

while in Mammalia the upper one is the most developed.

3380. The external auditory meatus is notwithstanding usually covered

by integument, the auditory ossicles are mostly blended into one, which

projects above the skull; the cochlea is wanting.

3381. Reptiles produce sounds for the first time through the lungs;

they have voice, but as yet no song.

3382. The nose, however, gives the finishing touch to the head. It has

not only opened as a vertebral canal in front, but also as a thoracic

cavity posteriorly into the mouth, which was not the case in Fishes.

The open nose is the æsthetic character of Reptiles, just as the red

muscles are the characteristics of the anatomical systems. The Reptiles

are _Rhinozoa_.

3383. The tongue takes a higher rank than in Fishes. It is throughout

soft, fleshy, and smooth; but in most species is still slit into two,

which reminds us of a similar condition of the penis.

3384. The teeth are in these animals more like digits than in Fishes.

While here they consist for the greatest part of front teeth, and are

therefore associated with the intestine, in Reptiles they are mostly

lateral, and thus true maxillary teeth, which are annexed to the

salivary system. With this special dental formation the saliva is also

more active; it is a rapidly fatal poison.

3385. The poison-teeth or fangs have likewise a groove, which can be

regarded as the continuation of the salivary duct.

_Class 12. Neurozoa, Otozoa._

3386. Those Sarcozoa, whose nervous system is for the first time

perfectly developed, and whose ear is open externally, are the _Birds_.

3387. The completion of the nervous system is the brain; now the brain

defines or determines the head; the Bird is, properly speaking, the

first Encephalic animal.

3388. In the Bird the head has for the first time, and that indeed

suddenly, freed itself from the trunk, and been placed upon a long

neck, far removed from the thorax. In no class are there such long

necks and so many cervical vertebræ to be found as in Birds. They can

be therefore called also Cervical animals, as the neck is not simply

present, in order to render the head independent or self-substantial.

The caudal vertebræ, on the contrary, are lessened throughout the

Birds, to a degree met with in no other class of animals.

3389. The brain separates for the first time completely into cerebrum

and cerebellum, begins to exhibit convolutions, and has in general

most of the individual parts analogous to those in the Thricozoa. They

are therefore _Encephalic animals_, which the name of Neurozoa will

properly enough imply. The nerves are in comparison with the spinal

cord much thinner than in Reptiles and Fishes.

In the Bird also, all the spiritual or mental faculties make their

appearance for the first time and suddenly, whereas in the preceding

classes but slight traces of them were observed. Such for example

are their mechanical instincts, varied modes of nidification, powers

of imitation, susceptibility to instruction, knowledge of their

benefactors, sentiment of joy, wheedling or coaxing manners, and so on.

We have no example of Fishes and Reptiles having learnt any artificial

tricks.

3390. Birds are the closest repetition of the Insects, but stand remote

from the Crabs and Acalephæ, indications of which are reflected by

their structure, disposition, mechanical instincts, and in their nests.

_Thorax._

As the sexual body with the tail predominates in Fishes, and the

abdomen in Reptiles, so does the thorax in Birds. The whole abdomen and

sexual body has been subordinated to the thorax.

The ribs are here directed in such a manner for the first time, that

the thorax can act as a voluntary pump-organ. Sternum and respiratory

muscles are usually large and peculiarly built.

3391. The lung is only a cluster of Insect tracheæ. They are full

of foramina, out of which the air can penetrate into the whole

body, exactly as in Insects. In Fishes the lung was still an actual

intestine, as seen in the single air-cyst; in Reptiles it was

nothing more than a double intestine; in Birds this lung is divided

after the fashion of an Insect into aerial vessels or ducts.

In the Bird the intestine lies in the air, and breathes from it, as in

the Insect. Birds are also animals which breathe by the intestine.

3392. The whole Bird is lung. Its body is a thoracic cavity, while in

the Fish it was simply a sexual cavity, and in the Reptile had obtained

the abdominal form. In Birds therefore there is a number of ribs and a

strong ossification, from the air itself penetrating into the bones.

Even the intestine has passed over into a motor organ. In Birds and

Insects only do we find a true muscular stomach, wherein the food is

crushed.

_Members or Limbs._

3393. In these animals the formation of limbs or members must be wholly

attained. Everything, that works, must work to the production of limbs.

The whole body becomes limb.

3394. With the perfected nervous and respiratory system the bones and

muscles make also a perfect appearance. The skeleton is hard, complete,

and full of air instead of marrow; the muscles are red and separated,

the movements free and complex.

3395. The elevated condition of the motor system is demonstrated in

the limbs, which here appear in the greatest diversity. There are only

two pairs of limbs, thoracic, and abdominal or sexual members. These

two are equivalent, so long only as the sexual and abdominal cavity

belonging to the trunk proper predominate, and therefore preserve the

equilibrium. But the limbs, which have been given to serve the office

of the trunk, are destined for progression or swimming, and are simply

terrestrial or aquatic members.

3396. The higher limbs are thoracic respiratory members, which are

filled with air and clothed with tracheæ, thus exercising a function

conformable to the thorax. The thorax has an aerial character. The

highest thoracic limbs must be aerial members.

3397. As the abdominal members move upon the earth or in the water, so

do the thoracic in the air. The terrestrial limbs are feet, the aerial

limbs, _wings_.

3398. The wings are in the member-formation the extremes of the

thoracic limbs. It does not follow from this that they are the noblest

in rank, but only that they are the uttermost unto which bodily motion

can attain.

3399. The winged animal is the Bird.

3400. The Bird is an Insect with fleshy limbs.

3401. The wings of Birds repeat the alary appendages of Insects in the

flesh.

3402. A Bird's wing is a strange but very instructive composition. It

consists, namely, of a Reptile's foot and an Insect's wings.

3403. We saw how the branchiæ of the Insect dried up, separated from

the feet, and being liberated as wings, were permeated by tracheæ. In

the Bird these wings have remained standing upon the feet and been

converted into feathers.

3404. A feather is an Insect's wing.

3405. As the Bird grows out at the thoracic limbs into the Insect's

wings, so does it upon the whole body into dried branchial laminæ.

The whole body of the Bird is clothed with branchial laminæ or plates.

3406. The wings of the Insects might be called free tracheæ.

The Bird's feathers are Insect-tracheæ. As in the Insect the wings are

a leash or net of tracheæ held together by membranes, so feathers are

tracheæ dividing into fibre-like ramules.

3407. The Bird is a Reptilian or Frog's body, beset all over with

Insects, like as with parasitic animals.

3408. The highest Insect only attains to the possession of four wings,

which in some Moths split again into several feathers. In the Bird a

vast number of such wings originates.

3409. An Insect's wing is not more than _one_ feather, and is therefore

placed also directly upon the body. These wings must multiply so soon

as they occur upon a membered trunk, upon arms. Thus, we need not ask

why the Butterfly has four, but the Bird only two wings, seeing that

the latter is the nobler animal. The discourse cannot be concerning the

wings of the former, for the Butterfly has indeed none, but only four

feathers.

3410. What the Bird is, it is by virtue of its feathers. It is

throughout a trachea, a pair of bellows. Its bones are hollow, full

of air, and stand likewise in communication with the lungs; the

feather-quills are also hollow.

_Senses._

3411. The wings have all the muscles to themselves; the bone has in

them gone to ruin. On the legs, on the contrary, the muscles have

declined, and the bone has got the upper hand.

Hence it results, properly speaking, that only the thoracic members are

perfected, because the Bird is nothing but thorax. The abdomen has,

so to speak, vanished, and through this the abdominal limbs are left

only, as thin and dry poles or staffs.

3412. From the same cause the muscular flesh upon the head has

disappeared. Neck and head are lean, or like Insect horn, which serves

only the nervous system.

3413. Beyond the excess of motion the sense of feeling has been nearly

lost. The toes are simply destined for motion, and to be used as

scrapers, and the digits have become the supports of feathers.

3414. The bill is an Insect's proboscis. In the Bird no teeth whatever

project from the flesh, but the jaws themselves. To such an extent has

the flesh been withdrawn. What has been called the cere is the only

remnant of the facial flesh. Even nostrils and tongue have suffered

ossification.

3415. The tongue is a feather. Saliva is scarcely present.

3416. The ears, as being the sense of motion, are far more perfectly

evolved than in all the preceding classes. They have opened outwards,

and possess an additional auditory part, the cochlea.

With the limbs the sense of hearing must of necessity grow perfect.

3417. The Bird is thoroughly, or "out-and-out" organized as an animal

of song. In it Nature attains unto a definite hearing and speech. The

Bird speaketh the language of Nature.

With the Bird, the voice, properly speaking, breaks forth for the first

time, and that too in a high grade of perfection, as melody.

3418. The ear is the highest representation of the trachea in muscles

and bones. The Bird is the _Otozoon_.

_Sexual Parts._

3419. The kidneys are symmetrically constructed, although not yet a

perfectly coherent mass. They are of very large size. But a strange

feature has come to pass in the urinary cyst, which is the sexual

lung. Into this, as has been already said, the intestine opens, and

thus it here again passes over into the lung, just as it has passed

over into a fleshy cardioid stomach, and completely upwards into the

feather-like tongue.

Into this sexual lung the seminal ducts also enter, or the penis, when

one is present, along with the oviduct.

3420. The ovum consists of two completely separated substances, and

these indeed are so distinct, that the vitellus is secreted at an

entirely different place to the albumen, the former in the ovarium, the

latter in the oviduct--whereas in Fishes both originated together.

The separation cannot extend further, or else the substances would no

longer unite with each other, and the vitellus must be first mixed with

the albumen, after it has been completely formed, after or when it is

an embryo. In the Bird albumen and vitellus come together during their

passage out of the parent's body, or in the act of being laid, and

thus before the albumen has been converted into the chick. But in the

Mammalia they are first completely united, subsequently to their being

laid--i. e. during the period of lactation.

3421. The vitellus is directly secreted from the arteries, but the

albumen from an enteroidal sac or the oviduct, which is finally

converted into mammary glands.

3422. The vitellus is more a product of the thorax, and is therefore

formed directly into the intestine and entire embryo.

3423. The albumen is an intestinal or digestive product, a solution of

the organic mass into protoplasma or primary mucus. It is not fashioned

itself into the embryo, but is only absorbed as fluid nutriment by the

latter.

3424. The shell of the ovum is the last bone, which the animal deposits

from the sexual blood, as being analogous to the urine. It is an aerial

product, or an analogue of the feather's quill.

3425. Even the nest of the Bird is a spiritual repetition of its

plumage, for in it the stalks of plants, tracheæ, or feathers are

united into one body, which reminds us in the Swallows of the Acalephæ.

FIFTH CIRCLE. AISTHESEOZOA.

_Class_ 13. _Aistheseozoa._

3426. An animal with all its organs of sense perfectly developed, is a

_Thricozoon_.

3427. The nervous system emerges at length freely above the other

systems, and it is no longer its mass, but its _organs_ which impart

character to the animal. The nervous organs are, however, simply the

organs of sense. Through these therefore must the present differ from

the preceding class of animals.

3428. Now too the senses first make their appearance in a

self-substantial manner above the other organs, serving merely their

own functions, and only by chance those of others.

3429. As in Birds the whole body was subordinated to the thorax, in

Reptiles to the abdomen, in Fishes to the sex, in Insects to the

tracheæ, and so on; in like manner is it here subordinated to the

system of the senses or the head.

3430. As the higher senses determine or define the anterior part of

the head, and are in their state of perfection provided with muscles;

so here the face or visage is invested by flesh, whereby, properly

speaking, a true, namely, a moveable countenance, first originates. The

Aistheseozoa have a _fleshy face_.

3431. All possess moveable eyes; fleshy noses, which stand open both

externally and internally; ears opening outwards, and mostly provided

with a moveable flap; a fleshy tongue, free in front, and moveable

lips; with at least thoracic limbs and a skin covered with hairs.

3432. In the Bird, Reptile, and Fish the face is merely invested by

tegument, nearly devoid of any muscles, and therefore immoveable.

They have a _tegumental face_, which is incapable of producing any

expressions.

3433. In the tegumental face the eyes are motionless, and very rarely

both directed so forwards that they can view an object together;

the nostrils are frequently devoid of a fleshy rim; the tongue often

feather-like, cartilaginous, or covered with teeth; true fleshy lips

are wanting, as are frequently the teeth, with even the limbs and

digits, or these are divided into a number of rays, forming either

feathers, or fins; in the Aistheseozoa there are never more than five

toes present, and if there be fewer, then the number admits of being

referred to some crippling of the normal quantity, five.

3434. It is remarkable, and serves to the discovery of many laws,

that the highest sense here appears for the first time in its state

of perfection. The eye in the Aistheseozoa is present in a perfect

condition throughout the class, with the exception of the eyelids; the

other organs of sense are, on the contrary, exhibited in all their

gradations of structure.

3435. It appears, as if the whole animal was first perfected, when

the eye is present with all its investment or clothing. The eye of

the Aistheseozoa has not simply all its internal chambers and all its

humours, but also all its muscles; it is moveable and has perfect

eyelids, with very few exceptions--_Ophthalmozoa_.

3436. The ear now begins to suffer arrest. Its completion is indeed

the formation of an external concha or flap for receiving the rays of

sound, the hand being repeated in the ear, and its skeleton constituted

by the auditory ossicles. This auditory hand occurs only in the

Aistheseozoa, and might serve as characteristic if it were not wanting

in many, while the eyelids are present. As in the Whales, where the

auditory passage can be, however, closed, an act which is not possible

in any Bird. The Bird must hear whether it will or no.

In all Thricozoa the interior of the ear is perfect, having cochlea,

semicircular canals, tympanum, and, as brachial parts, the three

conjoined auditory ossicles. The concha of the ear passes besides

through all stages of development, from having a simple margin to one

with most varied convolutions, lobes and opercula.

3437. Still more than the ear does the nose undergo modifications. In

the Whales it seems to be less adapted for the purposes of smell than

of respiration. The olfactory nerves are in them very delicate, and the

apex of the nose is destitute of motion.

In other beasts, on the contrary, it is elongated into a very muscular

proboscis or snout, and is endowed with the power of voluntary motion.

The form also of the nostrils is very varied, they being round, narrow,

patulous, and frequently capable of being closed.

3438. The tongue is indeed mostly fleshy and soft; yet in many species

it is provided with horny points, in others invested by a dense

coriaceous tegument, so that it appears to represent an instrument for

deglutition rather than gustation.

3439. The lips also are mostly fleshy and moveable; yet in many they

retrograde exceedingly and lose their mobility, as is partly the case

in the Ornithorynchus.

3440. In most, however, the limbs, especially the toes, are still

subject to variation. Their perfection consists in the number five, and

in the difference between the two pairs of limbs, as in Man. In the

Apes the posterior feet are also hands, which is an imperfection; in

the Marsupials there are hands posteriorly but toes in front; in other

respects there are generally toes, sometimes five, then four, finally

two perfect and two dew-claws in the Ox, and at length only one in the

Horse, while the posterior extremities are virtually lost in the Whales.

3441. The dental system, as being the set of maxillary claws, is alone

present in its state of perfection in the Thricozoa. They alone have,

in addition to the incisor teeth, all the five kinds of teeth that

differ from each other in form, namely, canine, false molars, laniary,

with second and third true molars, corresponding to the five fingers

reckoned from the thumb.

3442. In the dentition of those animals which tear their food the

greatest amount of completeness and variety is met with, since each

tooth has a different form and function.

In the Bears the molars are uniform in character, and so on through the

Apes up to Man.

In the Marsupials they are tolerably similar, as also in the Bats and

Shrew-mice.

They are still more alike in the Pig and Horse, and the incisor teeth

begin to be wanting in the Ruminantia, e. g. the Ox.

In Mice the canines are wanting, in the Sloths the front teeth, and in

the Ant-eaters actually all.

3443. In opposition to the perfect eye the general sense of feeling

is developed in the tegument. The tegument which is best developed

will be that, which represents a self-substantial organ with all its

appurtenances, and thus an organ of touch, whose nobility of rank

consists in motion. A skin, which is moveable by means of muscles, must

take the noblest rank. A skin with _tegumental_ muscles is an organ of

feeling, which is already in some degree subjected to the influence of

the will. If tegumental muscles do not occur in all these animals, they

still do in most of them.

The production of the most perfect coat or covering is the second step,

whereby the tegument ascends.

3444. Hitherto the outer covering of animals was pretty inorganic,

consisting either of hollow tracheæ, feathers, or semicavernous scales,

coat of mail, or lastly, only mucus. All these organs were only

constructed after the type of individual vegetable systems, in greatest

part only after the respiratory organ, and were therefore partial in

aspect or deficient.

The highest covering must also bear the highest meaning. This is that,

which grows out of the sanguinary system collectively, out of the

capillary vessels. The capillary vessels of the covering are, however,

the hairs. The hair is the most perfect covering of the animal.

3445. These animals are the _Thricozoa_.

Already the highest birds, e. g. the Ostrich and Cassowary, exhibit

feathers which merge over into hairs.

3446. An integument clothed with hair, and self-substantially moveable

is the perfection of this organ, it is a _fur_--_Furred animals_.

3447. The fur is the peripheric combination of the Vegetable and

Animal. The hairs are the highest Vegetable, as being the vascular

system grown out of or above the animal, and constituting the

fundamental or basi-system of the whole body. The tegumental muscles

are the lowest Animal. In the fur consequently the whole animal has

been represented, but as a limit set between animal and world.

3448. The tegumental covering also varies. The hairs become scanty in

respect of number; instead of them spines, horny rings or scales occur,

yet there are always hairs on the belly. In many Whales they seem to

dwindle into bristles. In some they have coalesced to form a kind of

bark, as in the Stellerian Walrus or Sea-cow.

_Thorax._

3449. In all the respiration is aerial; in all there is a true costal

structure, and a respiration effected through the motion of the ribs or

a pumping action; in all the lungs are filled with cells; in all there

is a diaphragm, a larynx, a trachea with cartilaginous rings, and a

thyroid gland. But the air no longer penetrates from out the lungs into

all the cavities of the body, as in Birds.

_Abdomen._

3450. The two intestines, namely, the large and small, are more

distinct from each other than in other animals; the cæcum coli is in

most distinct; the stomach expanded and membranous in texture, so that

it operates simply through chemical influence. Liver, pancreas, and

spleen occur in all.

3451. The sexual parts are in every respect very perfect. The penis is

present in all, and all have an uterus, fallopian tubes, and separate

oviducts. The penis is in many still retracted into a cloaca, and the

testes frequently lie within the abdominal cavity.

3452. As in the tegument the parts separate and each becomes

self-substantial, the fibre animal, the tegument vegetal, and so on

even in the sexual animal. The ovarium, consisting of two parts, now

also separates, since one becomes _animal_, but the other remains

vegetal. The albumen-organ becomes animal, detaches itself from the

sexual parts, is developed in the self-substantial tegument and called

mamma.

The Aistheseozoa are thus also _Mastozoa_ or Mammalia.

3453. This separation of the sexual animal is one of the first

characters. The mammæ could never be wanting, because they indicate

an essential stage in the development. The albumen-organ becomes an

organ of sensation. If the existence of mammary organs be doubtful, as

in the Ornithorynchus, the hairs are in that case perfectly distinct.

No Reptile nor Bird can have hairs, because their covering is derived

only from a partial system, the respiratory; while hairs are from the

general vascular system, which is the foundation of the tegument, of

the sense of feeling. The Ornithorynchus is a _furred animal_, and this

would suffice to bring it among the Aistheseozoa, were we even to deny

it mammary organs.

3454. Both sexes, male and female, have breasts. In youth they are most

readily detected in the male, because their sexual parts then rank

nearer to the female. In other respects the mammæ are probably the

chiefest organs of absorption for the embryo.

3455. The mammæ are nobler in rank, when, as udders they become

self-substantial; and the more they remove from the belly or abdomen,

and come, as breasts, to be placed upon the chest.

D. ORDERS AND FAMILIES.

3456. Had the names been given in strict accordance with rank; then

the class-divisions, which correspond to the circles, would have been

called _Orders_.

3457. Families would be class-divisions, which correspond to the

classes themselves.

3458. In no class therefore could there be more than four orders

admitted, or five, if the sensorial organs be reckoned to constitute a

special circle.

From the same reason there are no more than thirteen or seventeen

families.--These names cannot meanwhile be so strictly adopted, because

the classes are not of equal rank, as has been observed; on this

account it is necessary to shove in here and there other divisions,

which should be termed at one time _Cohorts_, at another, _Alliances_.

3459. If the animals of a class differ from each other, it is only

possible by their bringing to bear in addition to their characteristic

organ some other organ, and consequently becoming similar to an earlier

or later class.

3460. Yet nevertheless in this ascent the animals could never outstep

the confines of their own circle. There can be no Dermatozoon which

could have bones; for in that case it would be an Osteozoon, and belong

to another province.

Every class therefore comprises as many orders only as there are

circles with which it comes into contact. Thus in the first circle

there is only one order, in the second two, and so on.

Each class therefore includes also as many families only as the circles

which are touched by it contain classes. Thus the first to the third

class has three, the fourth to the sixth, six; the seventh to the

ninth, nine; the tenth and so on, thirteen.

3461. The serial arrangement of animals into families is naturally

difficult; but in Physio-philosophy we have to treat not about the

execution of the Systematic in detail, but concerning its principles.

FIRST CIRCLE. INTESTINAL, OOZOA--MUCUS-ANIMALS.

_First Class._

_Gastric, Vitelline Animals--Infusoria._

3462. The Infusoria admit of being reduced to three divisions:

the lowest of which, such as the Infusoria proper or Monades, are

provided for the most part with cilia; the next in succession, as the

Rhizopoda, possess extensible processes, and are mostly covered by a

multi-chambered shell; lastly, the most perfect Infusoria have all

kinds of internal organs, and especially what has been called rotatory

apparatus, as being the dawn of future tentacula.

3463. These three Families obviously correspond to the three classes of

the present circle, and that indeed as follows:

To the _first class_, or Infusoria proper, correspond the _Monades_.

To the _second class_, or Polyps, the _Rhizopoda_.

To the _third class_, or Acalephæ, the _Rotifera_.

3464. The Monades are obviously the simplest organized creatures, being

mucous vesicles, which move, obtain their food by stirring up vortical

currents in the water, and emit what is undigested again by the mouth.

3465. They occur very abundantly in all infusions, and can very well

originate, like Fungi, by division of the organic mass, although they

are in a condition to propagate themselves, i. e. by spontaneous

division.

3466. The Monades are the semen of the animal kingdom, which is

dissolved in, or rather produced from, the sea.

3467. The animal body is nothing else than a compound fabric of Monads.

3468. Decomposition is a separation into Monads, a retrogression into

the primary mass of the animal kingdom.

3469. All propagation, even that of the sex, commences like the animal

kingdom, or with its first family. On that account the embryonic

development must be a passage through the animal kingdom.

3470. The Rhizopoda usually adhere together within a multi-chambered

calcareous shell, out of which they protrude mucous filaments, and are

therefore the antetypes of the Corals or Polyps.

3471. The Rotifera exhibit all kinds of viscera, such as intestine and

ovaries; besides what have been called rotatory organs, which remind us

of the arms or tentacles of the Acalephæ.

3472. The families of these animals may be therefore aptly named as

follows:

Fam. 1. Typical Infusoria--_Monades_; cilia or vibratile organs.

2. Polypary Infusoria--_Rhizopoda_; extensible processes.

3. Acalephan Infusoria--_Rotifera_; intestine and oral organs.

_Second Class._

_Intestinal, Albuminous Animals--Polypi._

3473. The Polyps also do not admit of being divided into more than

three families. The first are only tubes or vesicles with _capillary

tentacula_ around the mouth, as the naked Polyps, Tubulariæ,

Sertulariæ, and Cellulariæ.

The others have true ciliated _tentacular rays_ surrounding the mouth,

and are always condensed inferiorly into a horny, and occasionally

stony axis or stem, as is seen in the Gorgoniæ, Alcyoniæ, and Isidiæ.

The third have ordinary _tentacula_, occurring in great numbers like

tassels or tufts around the mouth; their integument is either hardened

into stone, or becomes fleshy, as in the Star-corals and Actiniæ.

3474. There is no doubt that the _naked Polyps_ are closely allied to

the Infusoria, and among them indeed to the Rotifera, so that they

represent but a higher stage of these creatures, characterized by

superior size and by tentacular in place of ciliary or vibratile hairs.

3475. The _Cellulariæ_ cannot be more distinctly characterized than by

saying that they are cortices or ramules inhabited by Vorticellæ. Thus

they are Vorticellæ surrounded by a shell, and may be compared to ova,

in whose coriaceous or leathery shell calcareous granules are blended,

as in the eggs of the Crocodiles and Tortoises.

3476. They increase by means of ova and by ramification, if the former

mode of division is not carried too far.

3477. The tubes of the Tubulariæ appear to be nothing else than the

posterior extremity of the Polyp, desiccated or dried. These tubes are

not therefore the product of an excretion, but the body itself.

3478. On the contrary, the tubes of the Sertulariæ must be held as

being a tegumental excretion, within which the Polyp ramifies and

produces ova-cysts. If the naked Polyps resemble ova which are devoid

of shells, such as the roe or spawn of Fishes, then the Sertulariæ

resemble ova surrounded by a tough skin, like those of Rays and

Serpents.

The _Radiated Polyps_ or Horn-corals are invariably ramified and

converted towards their interior into a common horny or stony mass; so

that the animals themselves appear to have coalesced upon this into a

common tegument or bark. They possess a stomach and ovaries surrounding

it, which open into the border of the mouth between the rays. They thus

increase by ova and ramifications.

They therefore represent the class proper of the Polyps.

The tufted Polyps comprise the proper Corals or Lithozoa, are in form

and substance like the Acalephæ but with this difference, that the

covering is mostly lithoidal, while in many Acalephans, as the Porpitæ,

it only appears as a cartilaginous disc or plate.

3479. These Corals are true ova, having a perfect calcareous shell,

like that of the Bird. The gelatinous animal which adheres within

a wide-mouthed Madrepore, e. g. Fungia, resembles a vitellus just

hatched, and from which the foetal envelopes have been developed.

3480. The numerous tentacular filaments surrounding the wide mouth

resemble the shags of the chorion, which accumulate around the orifice

of the umbilical cord to constitute a placenta in the higher animals.

The Corals are brood-eggs inclosed within the uterus of Nature or in

the sea. The Coral-animals are an umbilical cord, treasured up for

the embryo, while the Tubulariæ are only membranous vitelli, and the

Gorgoniæ, ova with desiccated albumen.

3481. The families of Polyps stand therefore in the following order of

significance:

Fam. 1. Infusorial Polyps--_Tubulariæ_.

2. Typical Polyps--_Alcyoniæ_.

3. Acalephan Polyps--_Actiniæ_.

_Third Class._

_Absorbent, Involucral Animals--Acalephæ._

3482. The Acalephæ also can only be brought under three divisions, viz.

Röhrenquallen, or _Physaliæ_, Rippenquallen or _Beroes_, Hutquallen or

_Acalephæ_.

3483. The _Physaliæ_ are without doubt the lowest, being only giant

Infusoria; the _Beroes_ are allied through their simple bodily cavity,

to the Gorgoniæ; the _Acalephæ_, through their form, to the Madrepores,

especially the Actiniæ.

3484. They range therefore in the following order of significance:

Fam. 1. Infusorial Acalephæ--_Physaliæ_.

2. Polypary Acalephæ--_Beroes_.

3. Typical Acalephæ--_Medusæ_.

3485. The _first_ have not yet attained to the unity or single

character of the mouth, but imbibe their food through numerous tubes.

They are bundles of ramified Vorticellæ, a thoracic duct full of glands

and roots, which absorbs nutriment out of the sea, instead of an

intestine.

As the first family they are the antetypes of the Mussels and Entozoa,

and especially of the Hydatids and Tape-worms, and we shall not be

far from hitting the mark, if we compare their air-bladder with the

hindermost cystiform member of the body in the Hydatids.

3486. The _second_ family have a single mouth and ribs mostly full

of lamellæ, which are probably the antetypes of gills; they are also

frequently traversed by nutritive vessels.

They are antetypical of Snails, being in form an abdominal pouch, in

substance a liver, and frequently possessing paired tentacula. Higher

up, and they indicate the Crabs.

3487. The _third_ have, as a general rule, one central mouth

surrounded by four arms and very numerous vessels, which run from

the gastric cavity to its margins, and there mostly elongate into

filaments or hairs, being thus true lymphatic vessels, which convey

the nourishment directly from the stomach through the whole body, and

become on its margin tentacula.

3488. As antetypes of the Kracken they particularly manifest the form

of the Sepiæ, or Cephalopods, in the strong and frequently papillated

arms that surround the mouth. Gland-like nodes are also developed in

the margin of the pileus, but their meaning is as yet doubtful. Upon a

higher stage, and they are antetypical of Insects.

Their vascular system forms an exceedingly regular, quaternary net,

with branches and ramules ranging opposite to each other, which have

been believed to be the vitelline network of the ovum when hatched.

These vessels terminate likewise in a common marginal vessel, as in the

vitellus.

3489. Viewed as a whole they resemble in form, appendages, and

substance the foetal involucra or envelopes. The upper surface may

be compared with the convex back of the envelopes, the lower to the

concave funnel of the umbilical cord, and the succigerent filaments

or hairs to the shags of the chorion. They are probably elongated by

injection, like the so-called legs of the Star-fishes.

The secretion of the ova in four ovaries speaks also in favour of

their higher grade of development. They lie in four cavities around

the stomach, which also open near to the mouth. Their size also is

significantly expressive of their higher position.

Finally, they are of separate sexes. In them is the milt for the first

time distinctly displayed, and in the same situation indeed where in

other animals the ovaries are.

3490. Hence, in these three classes there are found no more than three

families, which together make up only _one_ order. The want of a fourth

family and so on, proves that the development of these animals does

not pass over into the succeeding circle. Their body therefore is only

an homogeneous, transparent mass, variously excavated and perforated,

but not separated into two cysts, namely, tegument and intestine, and

without the other viscera, which are formed by the vascular system,

such as the liver, kidneys, and salivary glands.

SECOND CIRCLE. VASCULAR, SEXUAL ANIMALS.

3491. These animals will both traverse the three classes of their

circle, as also repeat the preceding three classes, and they

consequently divide into two orders and six families.

_Fourth Class._

_Venous, Ovarial Animals--Mussels._

3492. The Mussels or bivalve Mollusca resolve themselves into two

orders, according to the structure of their mantle or respiratory sac.

It is either closed in a tubuliform manner, and opens posteriorly into

two mostly tubular-shaped respiratory apertures, and in front has an

orifice for the passage of the foot--_Camacea_ (_Lochmuscheln_); or

it is slit along its whole length anteriorly; and the pedal aperture

is confluent with the anterior and also indeed with the posterior

respiratory opening--_Ostracea_ (_Spaltmuscheln_.)

The first order still represent the cystic form of the Oozoa, and

partly by tubuliform calcareous shells placed around the two ordinary

shell-valves; but the second, by the freer development of the organs,

represent the animals of their own circle.

_Order_ 1. _Protozooid Mussels_--_Lochmuscheln_.

3493. These animals repeat the Mucus-animals; are tubular in form, and

mostly provided with two long respiratory tubes.

_Fam. 1. Infusorial Mussels--Sackmuscheln or Pholades._

Cylindrical, with a tubuliform mantle almost entirely closed and

frequently surrounded by a calcareous tube, in addition to the two

ordinary shell-valves; the pedal aperture is situated at the oral

extremity; the respiratory tubes retractile by means of muscles; the

foot is cylindriform.

Of the same kind are the Pfahlmuscheln, Teredines, and Sandmuscheln, as

also the Solenidæ. They typify the Nudibranchiate Snails and the Salpæ.

_Fam. 2. Polypary Mussels--Klaffmuscheln or Tellinidæ._

Body flat, mostly discoidal; there is a large fissure on the abdominal

side of the mantle for the passage of the foot, while posteriorly there

are two long respiratory tubes with retractor muscles. Here belong the

Tellinidæ and Venusidæ.

I have shown, that they are already to be recognized by the uncinate

or hook-shaped groove for the mantle in the shell, and which proceeds

from the insertion of the retractor muscles. The foot is usually

lancet-shaped. They typify the Patellæ and Ascidiæ.

_Fam. 3. Acalephan Mussels--Cardiacea._

Body globular in form, mantle having a pedal slit on the abdominal

side; two respiratory apertures without retractor muscles; foot mostly

uncinate or strap-shaped.

T have shown that these creatures are to be recognized by a discoid

groove in the shell, which simply depends upon the mantle, the

retractor muscles being wanting. Here belong the Cardiacea and gigantic

Chamidæ, in which last a byssus occurs, and the union also of the

two occlusor or sphincter muscles, as in the following order. They

antetypify the air-breathing Snails and Cirripedia.

_Order 2. Conchozooid Mussels--Spaltmuscheln._

3494. These animals represent their own circle.

The pedal slit in the mantle occupies the whole length of the latter,

and is confluent with the anterior or also with the posterior

respiratory aperture; so that only one or even no aperture is left,

and this when present is besides never elongated in a tubular form;

the retractor muscles are therefore wanting also, and the shell

simply exhibits a discoid groove for the mantle. The occlusor muscles

approximate and unite at their terminations. Both usually coalesce into

one.

_Fam. 4. Typical Mussels--Mytilaceæ._

Occlusor muscles separate, and mantle slit to such an extent, that only

the posterior respiratory aperture remains; foot mostly tongue-shaped

or coniform, with occasionally a byssus.

Here belong the fresh-water Mussels and the Mytili proper, of which

last many bore into rocks. They typify the Capulidæ and Brachiopoda.

_Fam. 5. Snail-Mussels--Arcaceæ._

Have two separate occlusor muscles and a perfectly separate mantle

without respiratory aperture; the foot small, mostly cartilaginous.

Here belong the Arcæ, Aviculæ, and Pearl-mussels.

They typify the Trochidæ and Pteropoda.

_Fam. 6. Kracken-Mussels--Ostracea._

Only _one_ occlusor muscle, mantle entirely open or slit, so that both

respiratory apertures are only oblique incisions therein; foot very

small, frequently furnished with a byssus. They typify the Buccinidæ

and Cuttle-fish.

_Fifth Class._

_Arteriose, Orchitic Animals--Snails._

3495. The Snails likewise divide into two orders, according to the two

circles, preindicated by the Ovum-and Sexual system. Their branchiæ are

either ramulate or pectiniform, the sexual parts combined or separated.

The first kind are still frequently gelatinous in texture, transparent

and naked; their branchiæ usually stand out freely as filaments,

lamellæ, or ramules upon the back, or lie simply as a vascular network

within the mantle. All are androgynous. They therefore obviously repeat

the Protozoa or Mucus-animals.

The second are invariably covered by the shell and by a mantle, within

the cavity of which the branchiæ lie concealed as one or two comb-like

bodies. Tentacula and eyes, which are occasionally wanting in the

preceding order, are here universally present; the sexes separate.

As in the Snails, the male parts make their appearance for the first

time distinct and individualized, and are also a characteristic organ

of the class; so also do they serve as bases of division, and the

Snails may be divided into those which are Androgynous or bisexual, and

those with separate sexes, i. e. Dioecious.

_Order 1. Protozooid Snails--Androgyni._

3496. The male and female sexual parts united together in a single

individual, branchiæ ramuliform, occurring either as filaments,

leaflets or ramules, freely situate upon the naked body, or as a

network lodged within the pallial cavity and surrounded by a shell.

The Nudibranchiate species live in the sea, those with hollow branchiæ

or the Pulmonea in the air; the former feeding mostly upon animals, the

latter upon plants.

_Fam. 1. Infusorial Snails--Notobranchiata, or Tritoniæ._

Body gelatinous and membranous, cylindrical and naked, devoid of shell,

with branchial filaments or ramules disposed in two rows upon the back.

Here belong the Tritoniæ and Dorides. Their body is muscular; the

tentacula not retractile; the male sexual parts open in company with

the female upon the right side of the neck, as in the higher organized

Snails. All inhabit the sea. They prefigure or typify the Salpæ.

_Fam. 2. Polypary Snails--Pleurobranchiata, or Patellæ._

Body and sexual parts as in the preceding family, the branchiæ,

however, occurring as ramules or leaflets upon the sides of the body,

are more or less covered.

Here belong the Phyllidiæ, Schüssel-and Schildschnecken. They are the

antetypes of the Ascidiæ.

_Fam. 3. Acalephan Snails--Dictyobranchiata or Limacidæ._

The branchiæ form a rete or network within the pallial cavity, and

respire the moisture of air; mantle and viscera are mostly surrounded

by a shell; the body is therefore bipartite, being separated into a

splanchnic or visceral body and a foot with head.

Here belong the Air-breathing Snails, both land as well as fresh-water

species. They typify the Cirripedia.

The shells are mostly thin and horny, yet nevertheless contain a

considerable quantity of calcareous earth, and are mostly devoid of

opercula.

Those species, which dwell in fresh water, do not possess introvertible

tentacula like the marine Snails, and the eyes are placed at their

basis; the sexual orifices are separate.

In the Land-snails, the tentacula are introvertible, and support the

eyes upon their apex; the sexual apertures are blended into one. The

former, like the marine Snails, lay numerous small ova inclosed within

a gelatinous mass in the water; the latter deposit their ova free,

covered with a membranous, and occasionally calcareous shell, in the

earth. Copulation is effected in all by a reciprocal interchange of the

androgynous species.

I have observed that individuals of Limnæa auricularia can continue to

propagate for several generations without being impregnated; they _must

impregnate themselves_.

_Order 2. Conchozooid Snails--Dioecii._

3497. Branchiæ situated within the cavity of the mantle, and hanging

down in the form of a comb; shell for the most part spirally contorted;

sexes separate--_Pectinibranchiata_.

Here belong the Capulidæ, Turbinidæ, Neritæ, Conidæ, Volutidæ,

Buccinidæ, Muricidæ and Strombusidæ.

The tentacula are not retractile, and have the eyes mostly seated at

their basis; the penis is external, very large, and cannot be drawn

within the body, but is only reflected into the pallial cavity; most of

them have a protrusile perforating proboscis, and an operculum. They

lay numerous small ova, contained within large membranous cases, which

frequently hang in rows to each other like a necklace of pearls. The

shells are in some instances horny, in others of a stony texture.

_Fam. 4. Mussel-Snails, Capulidæ._

Only one branchial comb within the mantle, and covered merely by a flat

hood-shaped shell; no operculum.

Here belong the Capulidæ; all the species are marine. They prefigurate

the Brachiopoda.

_Fam. 5. Typical Snails, Turbinidæ._

Two branchial combs, mantle devoid of a respiratory groove, shell

turbinated; mostly furnished with an operculum, and that indeed of a

stony texture. Here belong the Turbinidæ, and Trochidæ, such as the

Cyclostomata, Paludinæ, Ampullariæ, Janthinæ, Neritæ. Live in the sea

and in fresh-water.

_Fam. 6. Kracken-Snails, Buccinidæ._

Like the preceding family, but their mantle has a groove, and there

is a horny operculum. Here belong the Conidæ and Volutidæ, Buccinidæ,

Muricidæ, Strombusidæ. Almost all live in the sea and are of

sanguisugal habits. They antetypify the Cuttle-fish.

_Sixth Class._

_Cardiac, Nephritic Animals--Kracken._

3498. Body cylindrical, without sole or foot; frequently venous hearts

together with the arteriose hearts, and a kidney-like organ.

Such are the proper _Cylindrical Snails_, which are either sessile

or fixed, or move themselves by fins and what have been called

arms--Sessile and Natant Kracken. Here belong the Salpæ, Cirripedia,

Brachiopoda, Pteropoda, Heteropoda, and Cephalopoda. They all live in

the sea.

Branchiæ and sexual relations very varied.

They divide likewise into two orders, in accordance with the two

circles of Mucus-animals and Conchozoa; the former are spathiform,

mostly gelatinous, and firmly sessile or fixed; androgynous,

without head and rudders or fins. The branchiæ trellis-like and

filiform--Ascidiæ, Cirripedia and Brachiopoda.

The others have a kind of head with arms and eyes, or fin-shaped

steerage-organs upon the body; branchiæ pectiniform, reticular, and

leaf-shaped--Pteropoda, Heteropoda, and Cephalopoda.

_Order 1. Protozooid Kracken--Rumpfkracken._

3499. Body sacciform, mostly gelatinous, without head and eyes; species

androgynous. They are destitute of independent locomotion, most of them

being quite stationary or fixed, and surrounded frequently by a shell;

some few float about passively in the sea.

_Fam. 1. Infusorial Kracken--Salpæ._

The _Salpæ_ are gelatinous, freely natant cylinders, perforated by

an open tube, within which are situated the branchiæ, heart, mouth,

intestine, and liver, without any tentacula. They continue to hang for

a long time to each other, as though they were in the ovary.

They undergo a remarkable metamorphosis, which traverses two

generations, the young meanwhile not resembling the mother but the

grandmother.

Body within a sacciform mantle, with two opposite respiratory apertures.

_Fam. 2. Polypary Kracken--Ascidiæ._

The _Ascidiæ_ have a sacciform body with two co-approximate respiratory

apertures; branchiæ internal and trellis-shaped.

These gelatinous or cartilaginous animals adhere firmly to rocks, with

the respiratory apertures directed upwards as in the Mussels, but

the branchiæ are not foliiform; the internal cavity is lined with a

membranous sac, upon which the branchial vessels are dispersed in a

trellis-like manner. At the bottom of and within the sac is the mouth,

which is destitute of tentacula. Intestine, liver, and a heart that is

simple or undivided. Mode of propagation unknown.

They are frequently connato-sessile, like the Polyps.

_Fam. 3. Acalephan Kracken--Cirripedia._

Body sacciform, without branchial openings, oral apertures situated at

the inferior extremity of the longitudinal fissure in the mantle, and

provided with a kind of maxillary apparatus; above or behind the mouth

are annulate or horny filaments representing caudal fins or feet, upon

the basal joints of which is a branchial filament. Here belong the

Balani and Lepades--_Fuss-kracken_.

These animals are likewise sessile, at least when full grown, and

are surrounded by shell-plates, which remind us of the Echini or

Sea-Urchins, whose antetypes they are; this resemblance is particularly

distinct in the Balani, which have similar odontoid valves upon

the aperture or mouth of the shell. These animals also undergo a

metamorphosis, since in the early periods of their existence they swim

about like small Crustacea, and later on become fixed or sedentary, and

surrounded by the plates of shell.

The Lepades have the ordinary shells of Mollusca, but each of the two

valves consists of two pieces, between which an odd one is interposed

down the back.

These five shell-pieces become in the Balani a regular set of teeth,

which are adherent within the cylindrical shell, by which the

posterior part of the body, or the peduncular and elongated mantle, is

surrounded. (Vid. Oken's 'Allgemeine Naturgeschichte,' V, 1835, 509.)

They bear a resemblance to the Crustacea, not simply in the annulate

horny feet, but also in the double and ganglionic nervous chord lying

along the abdomen; only they are androgynous, which occurs in no

Crustacean.

_Order 2. Conchozooid Kracken--Kopfkracken._

Tentacula upon the head or fins upon the body. They repeat the

Conchozoa or Shell-animals.

_Fam. 4. Mussel-Kracken--Brachiopoda._

The body is surrounded by a mantle open above, and by two shells; on

the sides of the mouth there are two arms.

These animals look exactly like Bivalve Mollusca; they are firmly

adherent to rocks, being frequently supported upon a hollow pedicle,

which is a prolongation of the mantle. Branchiæ and sexual parts but

little known; species probably androgynous--_Armkracken_.

3500. In the following families the body is free and sacciform,

provided with arms or fins, and mostly with eyes upon a kind of head.

These animals have the mouth situated above or in front of the

body, and are distinctly separated into mantle and abdomen, while

they are frequently surrounded by a shell. They have a kind of head

with tentacles or arms, and frequently furnished with eyes like the

Snails, or pretty nearly like the Fishes; the sexual parts united and

separated. They all row, paddle, or steer themselves about in the sea.

_Fam. 5. Snail-Kracken--Pteropoda._

Body mostly gelatinous, sacciform, closed all round and free; fins upon

the sides of the neck, with two tentacula frequently projecting from

near the mouth; androgynous, naked, and inclosed within a shell.

These transparent animalcules swim about upright in the sea, and wave

the fins in this position as rapidly as a butterfly does its wings.

Most of them are covered with a spathiform and likewise transparent

shell. The branchiæ are placed externally on the body, but are not very

distinct. Several species have an appendage in front of the neck, which

is obviously a rudiment of the Snail's pad or sole--_Flugelkracken_.

The Heteropoda appear to resemble the Plantar or Sole-Snails,

but the body is mostly gelatinous, and the foot or sole is only

compressed to form a fin, so that they can only swim but not creep

with it. Many of them have a shell almost like that of the Argonauta.

Pterotracheæ--_Ruderkracken_.

_Fam. 6. Typical Kracken, Cephalopoda or Sepiæ._

Muscular animals inclosed within a sacciform mantle, open in front;

head furnished with eyes, and surrounded by more than four strong

prehensile arms; laminated or leaf-like branchiæ within the mantle,

sexes separate; in the body is a nephroidal or kidney-like gland, which

secretes a dark-coloured or inky fluid, on which account they are

called by us 'Dintenschnecken'--_Sternkracken_. They are obviously the

highest organized Malacozoa, and already remind us strongly of Fishes,

partly from their size, partly by their fleshy body, and in part by

their perfect organs of vision.

The body is often as large as the trunk of a man; the head being

separated from it by means of a neck, has in its interior a kind of

cartilaginous brain-case or skull, with externally a pair of jaws

resembling a Bird's beak, and with eyes tolerably similar to those of

Fishes. Auditory organs are also present, which consist of a tympanic

cavity inclosing an otolithe or ear-ossicle; nostrils are wanting. The

so-called arms are perfect organs of locomotion, as also useful for

seizing the prey, being provided for this purpose with sucking cups,

which adhere by producing a vacuum, when applied. In other respects

these arms are nothing else but the Snail's sole divided in front into

lobes. The ova resemble berries, and hang attached to one another

in branched clusters like a bunch of grapes. The Sepiæ possess a

remarkable gland, which is complicated with the liver, and secretes a

dark brown juice, which has been called ink or sepia; it probably ranks

in the significance of the kidneys.

Many are covered with a shell externally, as the Nautili and Argonautæ;

but in the common Sepiæ this shell adheres within the mantle upon the

back, and forms a straight lamina or plate, which is sometimes horny,

sometimes calcareous in its texture. It has been called the "white

fish-bone." What is regarded as the dorsal side of the animal is its

ventral side, because upon the former lies the pallial aperture and the

anus, while the vitelline sac is also inserted there.

In the form of the body, as well as in the circular position of the

cephalic arms, the Sepiæ strikingly resemble their antetypes, the

Acalephæ and Cirripedia, and their metatypes, the Asteriadæ and

Crustacea.

With these animals the second stage or circle through which the

Dermatozoa pass, or that of the Sexual animals, is closed. They require

only a slight additional grade of perfection, and they would pass over

into another class of animals. Thus were the arms to become horny and

articulate, they would be Crustacea; had the head a nose, and the body

consequently a myelon or spinal chord, they would then be Fishes.

SECOND CIRCLE. RESPIRATORY, CUTANEOUS ANIMALS--ANCYLIOZOA.

3501. Body annulate.

Here range the Worms, Crustacea, and the proper or volant Insects.

3502. In this circle a remarkable relation is revealed. If, namely,

its classes, orders, and families be compared with those of the two

preceding circles, it is then distinctly shown that the present one

again commences quite from below, ascends parallel with both these, and

transcends them in its highest inmates or members.

As an example of the first case, the imperfect condition of some

Entozoa, and their great resemblance to Infusoria, is sufficiently

expressive.

The Worms evidently pass parallel to the Mucus-animals, and the Entozoa

indeed to the Infusoria, the Red-blooded Worms to the Polyps, but the

Holothuriæ chiefly to the Acalephæ, near which they are still arranged

up to the present day, although they are articulated, and have an

intestine and vessels.

Thus this class traverses the three inferior classes, and consequently

imparts to them only the value of orders, or must itself be raised only

to the rank of an order, a step, however, which, considering the great

number of Worms, would not be suitable or just. The names may therefore

remain for the sake of uniformity; only it must be borne in mind that

they are of unequal value.

The same relation is exhibited in the Crustacea or Crabs. They

obviously admit of being parallelized with no other animals than the

Malaco-or Conchozoa. The Entomostraca and Crabs evidently repeat the

Mussels, the Aselli the Snails; but the Spiders and Scorpions the

Kracken or Cephalopoda. Consequently here also the orders correspond to

the preceding classes.

The true or proper Insects transcend the Sexual animals, and therefore

conform to the classification of their own circle, namely, they repeat

the Worms and Crabs, and finally mount forth upon their own stage.

The inferior or lower organized animals form consequently two series,

viz. the Smooth and Annulate, which in their lower members range

parallel, and that indeed after the following manner:

A. _Smooth._ B. _Annulated or Ringed._

I. _Protozoa._ I. _Worms._

a. _Stomach_, 1. Infusoria. 1. White-blooded Worms.

b. _Intestine_, 2. Polypi. 2. Red-blooded Worms.

c. _Absorbents_, 3. Acalephæ. 3. Holothuriæ.

II. _Conchozoa._ II. _Crustacea._

d. _Veins_, 4. Mussels. 4. Crabs.

e. _Arteries_, 5. Snails. 5. Aselli.

f. _Hearts_, 6. Kracken. 6. Spiders.

III. _Ancyliozoa._ III. _Flies._

g. _Retia_, 7. Worms. 7. Tracheoptera.

h. _Branchiæ_, 8. Crabs. 8. Dictyoptera.

i. _Tracheæ_, 9. Flies. 9. Ceratoptera.

The Worms have simply an annulate body with reticular or filamentary

branchiæ, but no feet; the branchiæ are supported by the body.

The Crabs have an annulate body with feet; the branchiæ are supported

by limbs.

The Insects have an annulate body with feet and wings; the body is

supported by the branchiæ.

_Seventh Class._

_Reticular, Papillose Animals--Worms._

_Protozooid Ancyliozoa._

3503. There are Worms with a soft body and white blood, without proper

tentacula; others with red blood, with and without tentacula, having

also bristles along the sides of the body; lastly, the rings of the

body become hard or muscular, and a circle or ring of osseous maxillæ

forms around the mouth, which is usually surrounded by numerous

tentacula, as in the Star-fishes and Holothuriæ, in whom the blood is

nevertheless colourless.

They divide accordingly into three orders, and each of these again

into three families, in accordance with the classes, namely, those of

the Protozoa or Mucus-animals, through which they pass.

_Order 1. Infusorial Worms--Parasites._

3504. The White-blooded Worms or Entozoa are very imperfect animals, a

fact which proves that this circle recommences quite inferiorly or from

below. They live for the most part in the interior of other animals,

being thus located in darkness and in places where they obtain but

little oxygen. Their blood therefore is not simply colourless, but

even its vessels are only imperfectly developed. They respire without

doubt through the tegument. In many, a distinct or separate intestine

being wanting, it is the tegument also which digests; in others the

intestine is simply a sac without an anus. The sexual parts too are in

many species of a doubtful character, while meantime there are both

androgynous and dioecious individuals. In the latter the male parts

open invariably at the posterior extremity of the body, as in Insects;

the female parts in front of its caudal end, as in the Crustacea. Both

are in other respects constructed as in Insects, namely, there are two

oviducts or seminal ducts, which unite before reaching their external

orifice. They divide into three groups.

In one of these the body is tolerably smooth, and the pharynx

commencing from a simple suctorial mouth elongates into a ramified

intestine without an anus; they are androgynous--_Saugwürmer_.

In others the body itself supplies the place of the stomach; it is

corrugated, and receives the food through one or several orifices,

without separating into a special intestine. They have nearly all a

claviform proboscis or rostrum, with which they perforate substantial

cavities for themselves; it would seem that they are both androgynous

and of separate sexes--_Hydatids_ and _Tæniæ_.

Others are separated into tegument and intestine like the Mussels

and Snails, but without having a distinct vascular system, heart,

and liver, though provided with a nervous chord and separate sexual

parts--_Ascarides_.

_Fam. 1. Monad-like Worms, Saugwürmer._

Body tolerably smooth, suctorial mouth and sucker, the intestine losing

itself in the tissue of the body, and without an anus; androgynous.

They remind us through their small size and structure of the Monades,

especially the Cercariæ, and among the Worms typify or prefigurate in

particular the Hirudines or Leeches, both by their form and power of

suction, as also in the ramification of the intestine.

Many Cercariæ might be metamorphosed into Distomata, and so be or

constitute their young.

The Planariæ are slightly different from the Liver-flukes or Fasciolæ

hepaticæ, since they are white, bloodless, have a ramified intestine

without anus, and increase also by fissiparous generation. They belong

to the present order, although they live not as parasites, but in a

state of freedom.

_Fam. 2. Rhizopodoid Worms, Hydatids._

Body annulate or articulate, with a claviform proboscis without an

intestine; they appear to have several mouths.

The _Cystica_ develop ova simply upon the internal wall of the

tegument; the body's last ring is expanded into a cystic form, and is

mostly much larger than the whole body. The Coenurus cerebralis, or

Brain-hydatid, ramifies like the Polyps.

The Cestoidea have in each joint or member of the body an ovarium, and,

as it would appear, male parts also, so that they are androgynous. The

sexual orifices are at the border or upon the surface of the posterior

members. The member can be viewed as an ovarium liberating itself; as

in the Lerneæ and Arguli.

The Filariæ or Thread-worms, which also belong here, are in the form of

a cylindrical tube, with separate sexual parts, which open posteriorly.

_Fam. 3. Rotiferal Worms, Ascarides._

Body cylindrical, intestine free, with mouth and anus; sexual parts

separate.

Upon the mouth these Entozoa have some papillæ or points, which may

be regarded as tentacula. The larger species have a distinct nervous

cord. The Gordius cannot well take any other position than the present,

although it does live in a state of freedom.

_Order 2. Polypary Worms--Hirudines._

3505. Body cylindrical with branchiæ in or upon the tegument, blood

red; two ganglionic nervous threads run along the ventral surface of

the body, as in Insects; all are indeed androgynous.

Here belong the _Red-blooded Worms_, as Hirudines, Lumbrici, Nereides,

and Serpulæ.

_Fam. 4. Tubularial Worms--Dermatobranchiata._

Body cylindrical. The branchiæ are only a vascular network in the

tegument.

Here belong the Hirudines and Lumbrici.

The Hirudines have a perfectly naked body, without filaments and

bristles, a perfect network of vessels containing red blood within the

tegument, an intestine with an anus, both sexual parts androgynoid;

posteriorly they have a pad or sucker; in the mouth there are mostly

maxillæ, and upon the head simple eyes.

The Naiades and Lumbrici have bristles in longitudinal rows upon the

sides of the body. The latter are androgynous. The Naiades increase by

division.

The Thalassemæ have a protuberant white body; red blood-vessels only

upon the intestine; mouth rostriform.

These Worms stick in the mud, and are nourished by it. They have here

and there bristles, but which do not form any longitudinal rows. They

appear to absorb water through the skin, and respire by the intestine.

They cannot, by reason of their red blood, range with the Holothuriæ.

_Fam. 5. Alcyonioid Worms--Notobranchiata._

Body depressed, with pedal filaments, tentacula and branchiæ in two

longitudinal rows upon the back.

These Worms all live in the sea, adhering mostly upright in the earth,

and have frequently annulate, rigid tentacula, ocelli, and pairs

of maxillæ, like Insects. The gills are not unfrequently covered

with pergamentaceous scales, as in many Nereides, and especially in

Aphrodite.

_Fam. 6. Actinioid Worms--Auchenobranchiata._

Body inclosed within a pergamentaceous or calcareous tube with lateral

bristles, branchiæ and tentacula upon the neck or head.

The neck is surrounded by a kind of mantle, almost as in the Snails, so

that several animals have been arranged here, which are now known to be

veritable Snails. Upon the head many have a horny operculum, whereby

they can close the shell.

Here belong the Amphitritæ, Terebellæ, Serpulæ, and Sabellæ.

_Order 3. Acalephan Worms--Sternwürmer._

3506. These creatures attain the most perfect structure of the Worms.

The blood is white, the form cylindrical, globular and stellate; the

mouth surrounded by a ring or wreath of maxillæ. The nerves form a ring

around the pharynx, and upon the latter are placed membranous cysts,

which spirt water into the tentacula or feet as they have been called,

and thereby expand them.

It is impossible for these animals to continue to range with the

Acalephæ, although they resemble them in outward form; for they consist

of two cysts, the intestine having become freed from the outer one as

a special sac; moreover, they have a perfect vascular system, distinct

muscles, a mouth with a dental apparatus, which prefigurates a complete

skeleton, a peculiar vascular system for the injection of the tentacula

or feet, a nervous ring surrounding the pharynx, an ovarium entirely

separated, and lastly, a perfectly annulate body.

_Fam 7. Physalial Worms, Holothuriæ._

Body cylindrical, very plentifully supplied with muscles. Mouth and

anus present, the former of these being surrounded by a dental wreath

and ramified branchimorphous tentacula; branchiæ upon the intestine,

and branchial aperture at the anal extremity. They correspond to the

Physaliæ.

Their tegument is a perfect muscular tunic, consisting of several

longitudinal bands, which pursue a downward course upon its internal

surface; in other respects being transversely corrugated and full

of papillæ, partly replete with hollow podoidal filaments, which by

the injection of water into them are elongated; thus, they present a

resemblance to the Acalephæ.

_Fam. 8. Beroeal Worms, Echini._

Are at bottom Holothuriæ with ossified tegument, or Asteriadæ with

shortened rays.

The Echini have an anus, pretty like that of the Holothuriæ, and also

similar feet, which are protruded in a similar manner through apertures

in the shell. The dental wreath surrounding the mouth is a complete

bony framework, which has been called, on account of its form, "Laterna

Aristotelis," and bears a considerable resemblance to the valves of the

Balani, the antetypes in general of the Echini, just as these are of

the Opossum Shrimps.

_Fam. 9. Medusal Worms, Asteriadæ._

Body stelliform, consisting of bony rings; contains a free multilobular

intestine with blood-vessels and branchiæ; several ovaria; it would

appear that they are without male parts.

Here belong the Encrinites, Pentacrinites, and Asteriadæ proper. Around

the mouth of the Encrinites and Pentacrinites stand long, ramified,

and likewise articulated tentacula, which remind us of the arms of the

Acalephæ and Cephalopoda.

Fundamentally too, in the Star-fishes, the disk only is the body

proper, and the rays are the tentacula, which, being monstrously

developed, surround the mouth; what have been called pedicles upon

these, represent the suckers of the Sepiæ.

_Eighth Class._

_Branchial, Pedal Animals--Crustacea._

_Conchozooid Ancyliozoa._

3507. The Crustacea are Worms with horny rings to the body, jointed

feet and tentacula, which mostly breathe by branchiæ.

They correspond to the Conchozoa, or Shell-animals, and divide

therefore into three orders, each of these including six families.

Here belong the Crabs, Wood-lice, and Spiders.

In the lowest forms the head, thorax, and abdomen are blended together,

and the back mostly covered with a great horny scute--_Mussel-like

Insecta_.

In the next place the thorax and abdomen admit of being clearly

distinguished, both by their form as well as by their appendages, which

are much larger on the thorax, as in the Cray-fish.

Then follow cylindrical forms with numerous feet, appended to uniform

rings, but having a head free and distinguished by tentacula, maxillæ,

and eyes--_Wood-lice_.

The Wood-lice bear a resemblance to the air-breathing Insects, although

all parts of the body still pass over or blend gradually into each

other.

In the _Arachnida_ or _Spiders_ aerial respiration takes place, and

their body enters into relations with the more highly organized

Insects, since the head becomes small, the abdomen large, thick, and

short.

As the Crustacea pass parallel to the Conchozoa or Shell-animals, so do

they divide into three cohorts or groups: the _Mussel-_, _Snail-_, and

_Kracken-like_ Crustacea, or _Crabs_, _Wood-lice_, and _Spiders_.

COHORT I. MUSSEL-LIKE CRUSTACEA--CRABS.

3508. Head and thorax connate, being mostly covered with a shell or

shield, abdomen stunted or caudiform; maxillæ and branchiæ present.

_Order 1. Lochmuschelartige, Pfriemenkrebse._

3509. The feet mostly simple and pointed, without large claws or

forcipes, and furnished with setæ or lamelliform branchiæ; eyes sessile.

_Fam. 1. Pholadoid, Mussel-Insects._

Small, almost microscopical, and slightly annulated animals with an

uni-or bi-valvular dorsal shield or testa, stunted maxillæ, and few

legs, having attached to them setiform branchiæ.

These animals are found in all stagnant waters, in which they are

incessantly paddling or rowing themselves about. They remind us of

those Infusoria which, like Brachionus, are covered by a scute or

shield. They are what have been called Monoculi (Entomostraca or

Lophyropoda), e. g. Daphniæ.

Number of feet small, and beyond their appended setæ there are no

branchiæ; two eyes frequently blended together; antennæ mostly furcate

like the feet; sexes separate; a perfect circulation within a true

Mussel-like ventral cavity. They are microscopic Mussels with eyes and

feet.

_Fam. 2. Tellinoid, Branchiopoda._

Similar animalcules to the above, but with a body strongly annulated,

naked or covered with a double shell, and provided with numerous feet,

unto which are attached leaflets that serve as branchiæ.

Here belong the Branchiopoda properly so called.

_Fam. 3. Cardiaceoid, Shield-Crabs._

Large animals, with strongly annulated body and numerous feet; head and

back covered by a shield, whereupon are the eyes--Phyllopoda.

Here range the Trilobites, Apus, and the Molucca or King-Crabs.

_Order 2. Spaltmuschelartige, Scheerenkrebse._

3510. Five pairs of thoracic feet, of which the first pair is mostly

large and forcipiform; the eyes upon moveable pedicles or foot-stalks.

These animals usually attain a striking size, and are generally the

largest among the horny Ancyliozoa.

The sexual parts open mostly upon the posterior legs.

The abdomen or tail usually supports five pairs of stunted feet, to

which the ova hang.

The number of maxillæ agrees tolerably well with that of the thoracic

feet.

_Fam. 4. Mytiloid, Locust-Crabs._

All the feet of pretty equal length, and the forceps stunted in size;

the branchial plates free upon the abdominal feet--Squilla.

_Fam. 5. Arcaceous, Macroura._

Abdominal feet arrested, branchial comb upon the femora of the thoracic

feet and beneath the dorsal shield, tail extended, as in the common

Cray-fish.

_Fam. 6. Oyster-like Crustacea, Brachyura._

Characters similar, but tail bent under the body--_Taschenkrebse_.

COHORT II. SNAIL-LIKE CRUSTACEA--ASSELN.

3511. Body mostly cylindrical, annulate, without a true carapax or

scute; head free; feet short and simple; branchiæ vesici-or folii-form;

mostly placed under the tail; eyes non-pediculated, or even wanting.

_Order 3. Androgynoid--Saugasseln._

3512. Body soft and slightly annulate, maxillæ, feet and branchiæ

arrested; live by suction as parasites upon other animals, mostly

fishes.

_Fam. 1. Tritonia-like, Lernæaceæ._

Body soft, without shield, eyes and branchiæ; feet and maxillæ stunted;

ova carried in two tubes at the hinder part of the body--_Kiemenwürmer_

or _Lerneæ_.

_Fam. 2. Patella-like, Argulaceæ._

Body distinguished into head, thorax, and abdomen, with few natatory

feet, maxillæ moulded to form suctorial organs, mostly eyes; lay also

strings of ova; head elongated in many in a scutiform manner. The

so-called Fish-lice or Argulaceæ.

_Fam. 3. Luftschneckenartige--Pycnogonidæ._

Body short, with four pairs of long feet; eyes, but no branchiæ and

maxillæ; abdomen puny in size. The _Whale-lice_.

_Order 4. Kammschneckenartige--Nagasseln._

3513. Body cylindrical, horny, and distinctly annulate, maxillæ, eyes,

and mostly seven simple pairs of feet, branchiæ as cysts or leaves.

_Fam. 4. Capulidenartige, Walzenasseln._

Body cylindrical, with five or seven pairs of feet, and some branchial

vesicles; body and abdomen very puny. The _Læmodipoda_; Caprella,

Cyamus.

_Fam. 5. Turbinidenartige, Seitenasseln._

Body horny and distinctly ringed, mostly compressed, with perfect

maxillæ; seven pairs of thoracic feet and branchial vesicles; abdominal

feet rudder-shaped. They swim usually lying upon the side; many

leap--_Amphipoda_; _Flohkrebse_ or _Gammarinæ_.

_Fam. 6. Buccinidenartige, Sohlenasseln._

Similar to the preceding family, but the body is depressed, and

the abdominal feet furnished with branchial plates. The _Isopoda_;

_Oniscidæ_, to which belongs the genus _Armadillo_.

COHORT III. KRACKEN-CRUSTACEA--KOBE.

3514. Body not tripartite; spiracula or air-openings; more than three

pairs of feet, no wings. Here belong the air-breathing Crustacea;

Scolopendræ, Acari, Scorpions, and Spiders.

These animals are abruptly distinguished from the preceding by a

conversion of the branchiæ into spiral-shaped tracheæ, which ramify

and traverse the whole body. They all therefore live in the air, and

if they do also dwell in the water, they still come to the surface to

inhale that element. The eyes are only simple points or ocelli, which

are accumulated frequently upon the sides of the head.

The most inferior of them are distinguished from the preceding cohort,

or the Asseln, by almost nothing save the essential character of their

own cohort, the tracheæ. They have mostly a number of feet, and only

simple eyes, as the Scolopendræ.

The following have a short body, in which the abdomen predominates;

thorax and head connate; never more than four pairs of feet--_Acari_,

_Scorpions_, and _Spiders_.

They likewise divide into two orders, like the Kracken.

_Order 1. Rumpfkrackenartige--Langkobe._

3515. Body horny, tolerably cylindrical and uniform; feet mostly very

numerous.

_Fam. 1. Salpoid, Spindelkobe._

Only three pairs of thoracic feet, but still podoidal appendages to the

abdomen--Podura, Lepisma.

_Fam. 2. Ascidioid, Schnurkobe._

Body cylindrical, with very many feet; sexual parts on the

thorax--_Juli_.

_Fam. 3. Cirrhopodoid, Bandkobe._

Body band-shaped and depressed, maxillæ perforate, sexual parts placed

posteriorly--_Scolopendræ_.

_Order 2. Kopfkrackenartige--Kurzkobe_.

3516. Body thick, mostly globiform; head and thorax blended together;

only four pairs of feet.

_Fam. 4. Brachiopodoid, Acarides._

Body rounded; all three parts confluent; usually only two simple eyes.

The Acari are mostly so small, that their parts can only be distinctly

seen through the microscope. Their mouth is always very much arrested,

and has maxillæ, which are in some cases adapted for manducation, in

others for suction.

_Fam. 5. Pteropodoid, Scorpions._

Body tolerably cylindrical, and all three parts connate; palpi very

large and forcipiform.

_Fam. 6. Sepioid, Spiders._

Body rounded, head and thorax connate, abdomen separate, mostly eight

simple eyes.

Their most remarkable organs are the four spinnerets in front of the

anus, which probably stand in the signification of the renal organs,

just as the material of the Spider-threads does in that of the urine.

The tracheæ are but few in number, and expand into lung-like vesicles.

The sexual parts do not lie posteriorly by the anus, but at the root or

base of the abdomen.

It is moreover remarkable, that their mandibles are perforated and pour

a poisonous juice into the wounds they inflict. They must be therefore

regarded, like the venom-teeth of Serpents, as elongated salivary ducts.

The Crustacean families can also be named according to the orders of

their circle, namely, the Worms and Crustacea, e. g. thus:

ORDER I. _Worm-Crabs_--Pfriemenkrebse.

Fam. 1. _Entozooid_--Mussel-Insects.

2. _Hirudinous_--Branchiopoda.

3. _Holothurioid_--Shield-Crabs.

ORDER II. _Crustacean Crabs_--Scheerenkrebse.

Fam. 4. _Typical Crustacea_--Sea-Mantes.

5. _Asselkrebse_ " --Macrura.

6. _Arachnoid_ " --Brachyura.

_Ninth Class._

_Tracheal, Alary Animals--Flies._

_Typical Ancyliozoa._

3517. Body tripartite, only three pairs of thoracic legs, spiracula

and wings. They divide, according to the classes of their circle, into

three cohorts, of Worm-, Crab-like, and perfect Flies.

As the wings are their characteristic organ, so also must

they be divided according to them, and not after the cibarial

instruments. Those wings which are developed to the least degree

are the homogeneous, transparent wings traversed by few tracheæ or

ducts--_Tracheoptera_, as Flies, Bees, and Butterflies.

Their chrysalis or pupa condition is perfect.

Then follow wings having very numerous veins united by transverse veins

so as to form a network--_Dictyoptera_, as Neuropterous, Orthopterous,

and Hemipterous Insects.

The pupa is moveable.

Finally, the anterior and posterior pair of wings become wholly

dissimilar to each other, the former being horny, and the latter

membranous in texture with reticulated veins, provided likewise with

joints like the legs, so that they can be folded up under the anterior

pair or elytra--_Ceratoptera_, as the Beetles.

Pupa state perfect.

Strictly speaking, it is a matter of indifference whether the names

of orders and families be adopted from the first or second parallel

series; whether e. g. we speak in the first cohort of Protozooid or

Worm-flies. The nearest series will, however, bear the greater amount

of resemblance to them. Meanwhile I will in the sequel vary in the

choice of names, in order to exhibit different samples of this double

parallelism.

COHORT I. WORM-FLIES--TRACHEOPTERA.

3518. Wings membranous with few longitudinal ducts, and almost devoid

of transverse ducts, eyes larger than head. Here belong the Flies,

Bees, and Butterflies. The abdomen is indeed annulate, but soft; its

first ring is frequently set free and unites with the thorax, but

supports neither feet nor wings.

The sexual parts always lie at the anal extremity.

The head is almost nothing but eye, and the Insects of this order may

very well be termed Megalopidæ, or large-eyed, out of contrast to the

succeeding ones. Between the two large compound eyes there are usually

found three simple ocular puncta or ocelli, which they have adopted

from the preceding class.

The larvæ are either entirely apodal, white and soft like Entozoa, or

they have, in addition to the thoracic feet, numerous abdominal feet

like the higher Worms.

The Flies with their soft and imperfect body, and the apodal larvæ,

repeat the Infusoria and Entozoa; the Bees therefore the Polyps and

Red-blooded Worms; the Butterflies with their large farinose or dusty

wings and polypodal caterpillars, the Acalephæ and Holothuriæ.

_Order 1. Entozooid Flies--Diptera._

3519. All the thoracic rings coalesced, and along with them the first

or basi-abdominal ring, unto which are attached the halteres or

balancers; only the two posterior wings present; the labium prolonged

into a proboscis, which incloses the setiform maxillæ. Larvæ apodal and

white.

The Diptera resemble the Entozoa in a striking manner through their

apodal, soft and white larvæ, and even through their habitation, which

is mostly in fetid and moist animal matters. Added to this, they

respire usually through two tubes which open upon the anus.

Many during their metamorphosis do not shed their skin; but it becomes,

during the pupa condition, only horny, representing a small case, whose

bottom springs up in front like an operculum, and gives exit to the

perfect Fly which has been therein developed.

Upon the first abdominal ring of the imago two nodose pedicles stand

out, which are called halteres; they are probably the old respiratory

tubes.

The maxillæ have changed into bristles, which act like pestels within

the groove-shaped labium, puncture and pump in the fluid.

They divide into three families like the White-blooded Worms, or

according to the orders of their cohort.

_Fam. 1. Typical Diptera, Schmeissen._

Antennæ triarticulate, the last joint being mostly spatulate and

furnished with a lateral awn or bristle; only two suctorial setæ

inclosed between the terminal valves of a fleshy proboscis, which

admits of being retracted within a large cephalic or oral cavity.

The Muscidæ, unto whom the Common House-flies belong, and also the

Hippoboscidæ or Louse-flies. It is my opinion too, that the Fleas also

are to be ranged among the Diptera.

Alliance 1. _Klappenmucken._ The two punctuating setæ placed between

two valves without a proboscis--Flea (Pulex) and Louse-fly (Hippobosca.)

Alliance 2. _Acalyptera._ Proboscis having thick lips, and

retractile into a large cephalic cavity; alulæ or halteral opercula

arrested--Hypocera to Dolichocera.

Alliance 3. Dung-flies. Characters similar to the above, but the

alulets are of considerable size--Muscidæ.

_Fam. 2. Hymenopteroid Diptera, Dasseln._

Antennæ as in preceding family, but the bisetaceous proboscis is

thin and horny, with small labia, or else large labia with four

setæ--OEstridæ, Conopidæ, and Syrphidæ.

Alliance 4. _Parasitic Diptera._ Two setæ with or without a lipless

proboscis--OEstridæ, Myopariæ, and Conopidæ.

Alliance 5. _Syrphidæ._ Four setæ within a similar kind of proboscis;

the third joint of the antennæ spatulate; the palpi thickened.

Alliance 6. _Leptidæ._ Four setæ within a short thick-lipped proboscis,

the third antennal joint mostly coniform--Therexidæ, Leptidæ, and

Dolichopidæ.

_Fam. 3. Lepidopteroid Diptera, Gölsen._

Antennæ multiarticulate and stipiform; proboscis with and without

labia, mostly four and six setæ for punctuation--Tipulidæ, Tanystomidæ,

Stratiomydæ, Tabanidæ.

Alliance 7. _Gnats._ Antennæ filamentary and multi-articular. Proboscis

varied.

Alliance 8. _Spiessmucken._ Four setæ within a hastate horny proboscis

with or without arrested labia; third antennal joint not annulated,

with the bristle or awn at the extremity--Tanystomidæ, as Asilidæ,

Empidæ, Bombylidæ.

Alliance 9. _Stielmucken._ Four or six setæ within a thick-lipped

proboscis; third antennal joint stipiform and annulated--Stratiomydæ

and Tabanidæ.

_Order 2. Leech-flies--Hymenoptera._

3520. Four naked veined wings, labium mostly elongated, the two pairs

of maxillæ acting above it like spears. Larvæ mostly apodal, or with

more abdominal feet or prolegs than in the true Caterpillars.

Most of the larvæ still bear a great resemblance to the Entozoa,

though they do not respire like them through the anus, but by lateral

apertures or spiracula; the larvæ with abdominal feet repeat the

Nereidæ and Aselli. In other respects they live no longer in putrid

moisture, fungi, roots, and such like bodies, but in living animals or

in cavities specially prepared for their reception by the parents, and

even in a state of freedom upon leaves.

And here is particularly worthy of our notice the structure of the

cells, which are by many species fabricated quite substantially of wax

or wood-shavings, and are to be compared with the webs of Spiders,

since both serve as nests for the young. They repeat the Polypidoms.

Others make cases of leaves, and carry into them honey upon which to

deposit their ova.

Others again simply bore holes in wood or in the earth, in order that

they may in a similar manner provide their young with honey or larvæ.

Finally, others simply stick, by means of their ovipositor, the ova

into animals or leaves.

The dwellings are fabricated by the maxillæ, which but seldom serve as

cibarial instruments, seeing that the labium undertakes this office as

a lick-organ.

Another remarkable feature of this order is the arrested development of

the sexual parts of the females in certain generations, an occurrence

which depends upon the time of the year or the size of the cells, and

whereby they are constrained to lead a social life as workers.

They divide, according to the Red-blooded Worms or the orders of their

cohort, into three families.

_Fam. 1. Dipteroid Hymenoptera, Bees._

Abdomen aculeate; labium elongated in a rostriform manner. They dig or

build cells, and carry thither honey to the larvæ, which are apodal.

Alliance 1. _Fossorial Bees_--Andrenidæ.

2. _Carpenter-Bees_--Anthophoridæ.

3. _Cell-Bees_--Apidæ.

_Fam. 2. Typical Hymenoptera, Wasps._

Aculeate; labium not elongated--rapacious Hymenoptera, such as Ants,

Fossorial, and Cell-wasps, larvæ apodal.

Alliance 1. _Hohlenwespen_--Formicidæ.

2. _Fossorial Wasps_--Sphegidæ.

3. _Cell-Wasps_--Vespidæ.

_Fam. 3. Lepidopteroid Hymenoptera, Terebrantia._

Instead of the sting there is an ovipositor, with which the females

stick their eggs into other insects, mostly into caterpillars, or else

into leaves and wood--Ichneumonidæ, Tenthredinidæ, and Uroceridæ.

The larvæ of the first are apodal, those of the second provided with

thoracic and abdominal feet like caterpillars, those of the third with

thoracic feet only like the larvæ of Coleoptera.

Alliance 1. _Stutzwespen._ Ovipositor short; wings nearly veinless.

Deposit their eggs in small insects; larvæ apodal--Chalcididæ, Oxyuri,

Chrysididæ.

Alliance 2. _Schlupfwespen._ Ovipositor very long, divided into

three hairs; wings veined. Deposit their eggs in caterpillars; larvæ

apodal--Ichneumonidæ, Evaniidæ.

Alliance 3. _Pflanzenwespen._ Ovipositor spiral or saw-shaped. Deposit

their ova in plants; larvæ mostly furnished with feet, and frequently

resembling caterpillars in form--Cynipidæ, Tenthredinidæ, and Uroceridæ.

_Order 3. Holothurioid Flies--Lepidoptera._

3521. Four veined wings, covered with small dust-like scales; maxillæ

have coalesced into a proboscis; larvæ with thoracic and abdominal legs.

The larvæ or Caterpillars remind us of the Nereides, especially the

setaceous Aphrodites, such as the Holothuriæ, and further still, the

Aselli and Scolopendræ. There are Caterpillars, which are scarcely to

be distinguished from a Wood-louse. They subsist almost throughout

upon leaves, and being exposed to the light are therefore variously

coloured. They have maxillæ, and in the labium is the orifice of the

salivary glands, from which they spin the threads used in weaving

their cocoons, or social tents. Where they crawl they leave, like the

Spiders, their threads beneath them.

The pupa state is perfect; the perfect insect generally creeps out of

the chrysalis by a slit taking place down the back.

The abdomen is almost throughout covered with hair, which is indicative

likewise of a strong mucous secretion.

They take in their fluid nourishment by suction, but the mechanism by

which this is effected is not yet known, as from the jaws themselves

forming the proboscis, there can be no suckers lodged within the latter

that might act. It is probably effected by expansion of the abdomen

taking place during respiration. Their deglutition would be therefore a

respiratory act.

Besides their very non-artistic webs, no artistic instincts are to be

observed in this order. The ova are just layed without more ado upon

plants, and rarely upon other objects. The Butterflies are generally

related to the plants, and especially to their corollæ, whose colours

and forms they carry in themselves.

They divide according to their proximal orders into three families.

_Fam. 1. Dipteroid Lepidoptera, Moths._

Antennæ filiform, wings mostly thrown like a mantle round the body;

proboscis short.

Small and nocturnal in their habits, proceeding from tolerably apodal

Caterpillars, which reside mostly concealed in plants, or make

themselves cases of hairs and leaves.

Alliance 1. Typical Moths, _Tineidæ_.

a. Typical Tineidæ: Alucitidæ.

b. Pyraloid: Tineæ.

c. Tortrix-like: Crambidæ.

Alliance 2. Bombycoid Moths, _Pyralidæ_.

a. Tinea-like: Aglossæ.

b. Typical: Hydrocampæ.

c. Tortrix-like: Deltoides or Herminiæ.

Alliance 3. Homalopteroid Moths, _Tortricidæ_.

a. Tinea-like: Fruit-Tortrices.

b. Pyraloid: Heterogeneæ.

c. Typical: Leaf-rolling Tortrices.

_Fam. 2. Hymenopteroid Lepidoptera, Silk-Spinners._

Antennæ filiform, wings tile-shaped.

Lepidoptera of considerable size, proceeding out of

Caterpillars, with many feet, and frequently covered with hair, which

live mostly in a state of freedom upon plants, and in some cases make

large cocoons freely exposed, in others under the earth--_Noctuidæ_ and

_Bombycidæ_.

Alliance 1. Moth-like Spinners, _Noctuidæ_.

a. Typical: Hadenæ.

b. Pseudobombycoid: Catocalæ.

c. Bombycoid: Erebidæ.

Alliance 2. Typical Spinners, _Pseudo-Bombyces_.

a. Noctua-like: Psyches, Limacodes.

b. Typical: Notodontæ.

c. Bombycoid: Callimorphæ.

Alliance 3. Homalopteroid Spinners, _Bombycidæ_.

a. Noctua-like: Bombyces.

b. Pseudo-Bombycoid: Saturniæ.

c. Typical: Hepialidæ.

_Fam. 3. Typical Lepidoptera, Homaloptera._

Antennæ varied; wings flat and expanded; proboscis long--_Geometridæ_,

_Vespertina_, _Diurna_.

Large Lepidoptera proceeding from free-living, strongly-coloured, and

mostly naked Caterpillars.

The Geometridæ have level, tolerably triangular wings and filiform

antennæ; they proceed from naked Caterpillars with few abdominal feet.

The Vespertina have level, long, and narrow wings, and spindle-shaped

antennæ; they emerge from perfect Caterpillars.

The Diurna have the wings folded upwards in a reverse position,

claviform antennæ, and proceed from perfect Caterpillars.

Alliance 1. _Moth-like Homaloptera, Geometridæ._

a. Typical: Geometræ.

b. Sphingoid: Aposuræ.

c. Papilionaceous: Uraniidæ.

Alliance 2. _Bombycoid Homaloptera, Sphingidæ._

a. Geometroid: Zygænidæ and Sesiadæ.

b. Typical: Sphingidæ.

c. Papilionaceous: Castniæ.

Alliance 3. _Typical Homaloptera, Papilionidæ._

a. Geometroid: Hesperiidæ, Lycænidæ and Erycinidæ.

b. Sphingoid: Nymphalidæ and Heliconiidæ.

c. Typical: Pieridæ and Papilionidæ.

COHORT II. CRUSTACEOUS FLIES--DICTYOPTERA.

3522. Four wings, with longitudinal and numerous transverse veins, the

anterior pair being mostly leathery in texture; eyes mostly smaller

than head.

Here belong the Neuroptera, Orthoptera, and Hemiptera.

The metamorphosis is tolerably imperfect, and the larvæ have never more

than three pairs of thoracic feet, and therefore correspond no longer

to the Worms, but to the Crabs, where the number of the feet has been

already more determined. Many also strikingly simulate the Crustacea.

In all three families also the pupa runs about, eats, and has rudiments

of wings.

The abdominal rings are mostly horny and hairless. The spiracula lie

upon the upper margin.

The eyes are generally much smaller than the head, and may therefore,

in comparison with those of the preceding and subsequent groups, be

said to be of _middling size_; the simple eyes have for the greatest

part disappeared. Meanwhile the first family displays _large eyes_, the

second eyes of a _middling size_, the third _small eyes_.

They divide like their antetypes, the Crabs, into three orders.

_Order 4. Crab-Flies--Neuroptera._

3523. All the wings alike and membranous; maxillæ with mostly large

eyes; abdomen soft.

These Insects which, on account of their delicate wings, are known with

us by the name of Flohrfliegen, live mostly upon flesh, and many of

them by capturing living prey. Many undergo a short pupa stage. Many

live in the water and have, too, branchiæ, whereby they strikingly

remind us of the Crustacea, especially the Branchiopoda.

Like the Crustacea, or in accordance with the two first cohorts of

their class, they divide into two families.

_Fam. 1. Tracheopteroid Neuroptera, Nagbolden._

Do not subsist by rapine, but gnaw slowly animal and vegetable matters;

many also as flies eat no longer.

Alliance 1. _Dipteroid Neuroptera, Kieferläuse._ No wings; gnaw skin,

feathers and hair, mostly Bird-lice--Philopterus, Liotheum.

Alliance 2. _Hymenopteroid Neuroptera_, Blumen-and Mulmlaüse, Thrips,

Psocus, Termes.

Alliance 3. _Lepidopteroid Neuroptera_, _Phryganeidæ_ (_Wassermotten._)

_Fam. 2. Dictyopteroid Neuroptera, Raubbolden._

Alliance 4. _Typical Neuroptera, Flohrfliegen_, Panorpidæ, Hemerobiidæ,

Myrmeleonidæ.

Alliance 5. _Orthopteroid Neuroptera_, Raphidiidæ, Mantispidæ.

Alliance 6. _Hemipteroid Neuroptera_, Ephemeridæ, Libellulidæ.

_Order 5. Oniscal Flies--Orthoptera._

3524. Maxillæ and dissimilar reticular wings; the anterior,

pergamentaceous; abdominal rings, horny; eyes of moderate size; pupa

moveable.

Live for the greatest part on plants.

_Fam. 1. Tracheopteroid Orthoptera, Saltatoria._

Alliance 1. _Dipteroid Orthoptera_, Grylli.

Alliance 2. _Hymenopteroid_ " Locustæ.

Have a hard ovipositor, which reminds us of the sting in the

Hymenoptera.

Alliance 3. _Lepidopteroid Orthoptera_, Acrydia.

_Fam. 2. Dictyopteroid Orthoptera, Cursoria._

Alliance 4. _Neuropteroid Orthoptera_, Mantidæ.

Alliance 5. _Typical_ " Blattidæ.

Alliance 6. _Hemipteroid_ " Forficulidæ.

_Order 6. Arachnoid Flies--Hemiptera or Bugs._

3525. Horny suctorial proboscis with puncturating setæ; dissimilar

reticular wings, the anterior mostly pergamentaceous, the posterior

membranous, and mostly capable of being folded up, as in the Chafers;

eyes small, pupæ moveable.

The Bugs have much resemblance to the Mites, and Spiders are as it were

winged Mites. One party of them suck blood, another vegetable sap.

They manifest no artistic instincts.

The Aphides or Leaf-lice require only a single pairing, to enable

them to propagate through several generations. During the summer they

produce only females, and in autumn the males first appear.

_Fam. 1. Tracheopteroid Hemiptera, Leptoptera._

Alliance 1. Dipteroid Hemiptera, _Coccidæ_, _Aphidæ_.

Alliance 2. Hymenopteroid " _Cicadæ_.

Alliance 3. Lepidopteroid " _Fulgoridæ_.

_Fam. 2. Dictyopteroid Hemiptera, Pachyptera._

Alliance 4. Neuropteroid Hemiptera, _Water-bugs_.

Alliance 5. Orthopteroid " _Narrow bugs_,

_Hydrometræ_, _Reduvii_, _Cimicidæ_.

Alliance 6. Typical Hemiptera, _Broad bugs_, _Capsidæ_,

_Lygæidæ_, _Coreidæ_, _Scutelleridæ_.

COHORT III. PERFECT FLIES--CERATOPTERA, BEETLES.

3526. Maxillæ and dissimilar reticular wings, the anterior being

horny, the posterior membranous and susceptible of being folded upon

themselves; eyes small; pupæ motionless.

The Chafers or Beetles are the highest Insects, because they possess

the greatest variety of organs, namely, two kinds of wings; not to

mention the perfect condition of their manducatory apparatus, antennæ,

and the first thoracic ring which is free.

The Beetle represents the Flies in their entire perfection; everything

is rendered horny in the former even to the lower wings, which are

furnished with several joints, almost like the feet. The upper wings

are horny and meet together so closely by their inner margins upon the

back, that they form a closed suture, like the shells of the bivalve

Mollusc. The antennæ are also more perfect than in other families,

and mostly jointed like the feet, while at their extremity they are

frequently thickened into laminated moveable clubs, which open when the

animal would fly, as if to listen.

Their habitation, mode of living and subsistence is exceedingly

complex, and therein also they combine again all the families of this

class, and it might be said, all the preceding classes.

The Beetles are also much more numerous than any other order, and could

in this point of view even hold good for an entire class, especially,

if they represented a special organic system, but which is not the case.

They live upon vegetable saps, and matters, blossoms, leaves, and wood,

living animals, putrid flesh, dung, and such like.

They dwell mostly indeed in concealed situations, but also in those

that are freely exposed, while many live in water, and are so subjected

to its influence that their larvæ actually respire this element through

branchiæ.

The larvæ are white and have three pairs of horny thoracic feet. They

live concealed.

The pupæ are invested by a transparent tegument, which tears in an

irregular manner.

The Beetles divide distinctly into three divisions, which correspond to

the three cohorts of this class, or repeat the three cohorts of their

circle.

The Beetles have been pretty generally divided according to the number

of tarsal joints into those having three, four, five, or an unequal

set of these "articuli," whereby, however, the greatest disorder has

originated. I have therefore divided them in my 'Naturgeschichte'

according to their mode of living into _Phytophaga_, _Sarcophaga_, and

_Rypo-_ or _Coprophaga_, which gradually seems to meet with approval.

At least a much more natural arrangement comes to light by using these

means.

I have also declared the Rhyncophora to be the lowest and the

Lamellicornes the uppermost in rank, a view, which at present appears

to be generally adopted.

By these means I obtained two firm points, whereby the division or

classification of the intermediate members is uncommonly facilitated,

although many may still stand in the wrong place. But who can point out

a single system in which Insects range correctly, or, what is more,

wherein it would not be easy to prove that no single order and family

occupies the right place.

In such trumpery systems of classification, one would think, that some

respect might be had for principles, or at least a feeling of shame for

the blockhead's weakness of intellect. But in vain! Where the sense for

philosophy or for principles is wanting, it is not to be inculcated

or driven in. We still see Natural Histories shoot forth, with whose

shrub-like ramification we must have compassion. Every thicket of

briars is rooted deep, and admits only of being extirpated by wearisome

and patient culture.