mentioned are for the most part those which have already been alluded to in
the preceding account:—
Sub-class I. ENTOPROCTA.
_Loxosoma_, _Pedicellina_, _Urnatella_.
Sub-class II. ECTOPROCTA.
Order 1. Gymnolaemata.
Sub-order 1. Cyclostomata.
A. Articulata. _Crisia_.
B. Inarticulata. _Hornera_, _Idmonea_, _Tubulipora_, _Stomatopora_,
_Diastopora_, _Entalophora_, _Lichenopora_.
Sub-order 2. Cheilostomata.
A. Cellularina. _Aetea_, _Eucratea_,[589] _Catenicella_,
_Cellularia_, _Gemellaria_, _Menipea_, _Scrupocellaria_,
_Caberea_, _Notamia_ (= _Epistomia_), _Bicellaria_, _Bugula_,
_Beania_.
B. Flustrina. _Cellaria_, _Flustra_, _Membranipora_, _Electra_,
_Lunulites_, _Membraniporella_, _Cribrilina_, _Micropora_,
_Selenaria_.
C. Escharina. _Retepora_, _Microporella_, _Lepralia_, _Porella_,
_Smittia_, _Mucronella_, _Schizoporella_, _Schizotheca_,
_Mastigophora_, _Porina_, _Cellepora_.
Sub-order 3. Ctenostomata.
A. Alcyonellea. _Alcyonidium_, _Flustrella_.
B. Vesicularina. _Vesicularia_, _Amathia_, _Bowerbankia_,
_Farrella_, _Hypophorella_, _Triticella_, _Mimosella_,
_Victorella_, _Paludicella_.
Order 2. Phylactolaemata.
_Fredericella_, _Plumatella_ (including _Alcyonella_), _Lophopus_,
_Cristatella_, _Pectinatella_.
{519}Even this classification, which deals only with the larger groups,
must not be made use of without a word of warning. The division of the
Cheilostomata is a matter of great difficulty; and no scheme which has yet
been suggested can be regarded as more than tentative. The great number of
forms included in this group makes its subdivision extremely desirable from
the point of view of convenience; but a further knowledge of the anatomy
and of the development of many of the forms of doubtful systematic position
is probably necessary before any scheme which is likely to be permanent is
put forward. Those who desire to make a further study of the classification
of the Polyzoa should refer to the works of Hincks,[590] Busk,[591]
MacGillivray,[592] and Gregory.[593]
The Polyzoa do not appear to lend any valuable assistance towards settling
the disputed problems of Geographical Distribution. They are not in any
case terrestrial, while the fresh-water species do not always respect the
limits between the great zoogeographical regions. It has already been
pointed out (p. 504) that _Plumatella_, _Fredericella_, and _Lophopus_ are
believed to occur in Australia, and the first-named genus is practically
world-wide in its distribution.
Many marine forms also have a surprisingly wide distribution. Thus among
the British species which are described by Mr. Hincks as occurring from
Norway to New Zealand are _Membranipora pilosa_, _Scrupocellaria scruposa_,
_Cellaria fistulosa_, _Microporella ciliata_, and _M_. _malusii_. Even if
it should be proved that specific differences do exist between the southern
forms and our own, there can be no doubt of the wide distribution of
certain species. It was pointed out by D'Orbigny that _Bugula neritina_ has
the habit of attaching itself to the bottoms of ships, a fact which may
possibly account for the wide distribution of this species; although it
would not be safe to assume this explanation of the facts in all cases.
Other Polyzoa, on the contrary, have a more restricted range. Thus
_Catenicella_ is specially characteristic of the Australian region.
It is perhaps surprising that marine Polyzoa should in so many cases have
so wide a range. Even though it is the rule {520}for Polyzoa to have free
larvae, the period during which these larvae are free-swimming is, so far
as is known, a short one in most cases. _Cyphonautes_ is a common pelagic
form (see p. 510), and probably remains for a considerable period in the
larval condition. Other Polyzoon-larvae appear to fix themselves very soon
after their birth; and this would not appear to give much time for them to
be carried to great distances by ocean-currents. It may, however, be
suggested that it does not follow that because we know that a larva may,
under favourable conditions fix itself a few minutes after it becomes free,
we should be justified in assuming that that larva would not retain for a
long period the power of undergoing a normal metamorphosis should it be
drifted away from suitable fixing-grounds.
PALAEONTOLOGY.[594]—The number of fossil Polyzoa is enormous. D'Orbigny
devoted two hundred plates and more than a thousand octavo pages[595] to a
Monograph on the Cretaceous Polyzoa of France. Many of the fossil forms are
extraordinarily well preserved, and there is often no difficulty in
recognising the identity between certain fossil species belonging to the
more recent formations and living forms. It thus becomes necessary to
consult Palaeontological memoirs in working at recent Polyzoa.
While the great majority of fossil Polyzoa do not differ in any essential
particular from recent species, this is not altogether the case with the
Palaeozoic forms. Leaving out of account the Stromatoporoids, which have
been variously referred to the Sponges, Hydrozoa, and Foraminifera, as well
as to the Polyzoa, the Palaeozoic strata contain large numbers of peculiar
Cyclostomata, together with members of the Trepostomata, a fourth Sub-order
of Gymnolaemata, allied to the Cyclostomata. The Trepostomata are for the
most part Palaeozoic, but a few survived as late as the Jurassic
period.[596] These, with the other Polyzoa from the same formations, are
considered by Dr. Gregory in his recently published _Catalogue of the
Fossil Bryozoa in the British Museum_ (1896).
The number of Polyzoa recorded from the earlier secondary strata is small.
The majority of the known Jurassic forms {521}belong to the Cyclostomata;
and one or two Cheilostomes are recorded from the same period. Recent
papers by Walford[597] on Jurassic Polyzoa contain the description of
genera which are believed to be intermediate between the Cyclostomata and
Cheilostomata, particularly with regard to the characters of their
ovicells. Although it is not impossible there may be a connection between
the ovicells of these two groups, it has yet to be proved that the two sets
of structures are homologous.
The Cretaceous period marks the commencement of a large number of
Cheilostome genera, although the Cyclostomes still remain numerous.
In the Tertiary formations the Cyclostomes gradually become less numerous,
and although in earlier geological periods they far outnumbered the
Cheilostomes, these relations are now reversed. Certain Tertiary strata,
and particularly the Coralline Crag (Pliocene), are remarkable for the
extremely large number of Polyzoa they contain. It will be noticed that no
mention has been made of the Entoprocta, the Ctenostomata, and the
Phylactolaemata. Their absence in the fossil condition[598] need not,
however, be a matter for surprise, as none of these forms are so well
suited for being fossilised as are the calcareous Cyclostomata and
Cheilostomata. There is consequently no adequate reason for assuming that
the absence of a palaeontological record implies that these groups have
been recently evolved.
DETERMINATION OF GENERA OF MARINE POLYZOA.—The species to which a Polyzoon
belongs can only be determined, in most cases, with the assistance of the
low powers of a microscope. There are very great advantages in the use of a
binocular instrument, by means of which a microscopic preparation appears
with its parts standing up in proper relief.
In the case of the calcareous forms, the external characters may be more
readily made out in a dry preparation than in any other way. For this
purpose, the colony should be washed with fresh water, in order to remove
the salts, which otherwise crystallise out on drying and obscure the
surface. Preparations of this kind must be looked at with the aid of
reflected light. Canada-balsam or glycerine preparations are also valuable,
whether {522}stained or unstained; and are essential for the examination of
the softer forms. In the case of erect species, both surfaces of the branch
should be looked at. The opercula, avicularia, and rosette-plates afford
important systematic characters in the case of the Cheilostomata.
It must not be forgotten to take account of the condition of the zooecia at
different ages. The old zooecia often become entirely altered in form, by
the deposition of additional calcareous matter, or by the loss of certain
parts present in the younger zooecia. Thus the marginal spines may be
entirely lost in the older individuals, while in those forms which develop
a "peristome" (see Fig. 255 and p. 524), the characters of the orifice can
often be determined in the young zooecia only. It is thus essential to
examine the growing ends of the branches or the rim of the colony, as the
case may be.
[Illustration: FIG. 255.—Illustrating the nature of a secondary orifice
(Cheilostomata). A, _Mucronella coccinea_ Abildg., Scilly Is., × 40. The
ovicell (_o_) overhangs the primary orifice, which is concealed by the
great development of the peristome, produced into the mucro (_mu_); _t_,
the three teeth (denticles) within the secondary orifice; _a_, avicularium.
B, _Porella compressa_ Sowb., Norway, × 40; _p.o._ primary orifice, above
which is a concave lamina, the beginning of the ovicell. In the lower
zooecium the ovicell (_o_) is further grown. The primary orifice is still
visible, but it is partially concealed by the growth of the peristome,
which encloses a minute avicularium; _m_, mandible of avicularium. C, Older
part of the same colony; _pr_, peristome; _s.o_, secondary orifice; _o'_,
adult ovicell; _p_, pores.]
In order to make preparations with the tentacles expanded, hydrochlorate of
cocaine, chloral hydrate or spirit should be added gradually to the water.
When the animals are completely anaesthetised they may be killed by means
of a 7-10 p.c. solution of sulphate of copper (best made in distilled water
or in rain water). This method gives admirable results in the case of both
{523}fresh-water and marine Polyzoa. The use of formaline (see p. 229) may
be strongly recommended for the Vesicularina.
The only recent work dealing with all the marine BRITISH FORMS is Mr.
Hincks' invaluable _History of the British Marine Polyzoa_.[599] As the use
of this book, unaided by any artificial help, is by no means easy to the
beginner, the following key has been compiled as an index to the genera.
The Entoproct forms, _Loxosoma_ and _Pedicellina_ (see pp. 488-491), are
not included in the table.
[Illustration: FIG. 256.—Illustrating the terminology of the front surface
of the zooecium (Cheilostomata). A, _Membranipora_ (_Electra_) _pilosa_ L.,
Cromer, × 47; _ap_, the membranous "aperture;" _o_, orifice. B,
_Membranipora flemingii_ Busk, Plymouth, × 60; _ap_, the aperture, enclosed
in a calcareous "area" (_a_); _av_, avicularium; _s_, marginal spines. C,
_Micropora coriacea_ Esper, Plymouth, × 43; _a_, area (calcareous); _o_,
operculum; _ov_, ovicell.]
In order to facilitate the use of the table here given in conjunction with
Mr. Hincks' work, the nomenclature there adopted has been followed
throughout. References to other descriptions of the species may be obtained
by consulting Miss Jelly's admirable _Synonymic Catalogue of the Recent
Marine Bryozoa_.[600]
TERMINOLOGY.—A few technical terms must of necessity be employed. The
colony is _adherent_ when its zooecia are attached to the object on which
the colony is growing. The _zooecium_ is the body-wall of a single
individual; and, except in transparent species, is the only part which can
be seen from the outside in the retracted condition of the _polypide_ or
tentacles with the alimentary canal. The outermost layer of the zooecium is
known as the _ectocyst_; it may be simply membranous, or calcified, or may
be rendered opaque by foreign bodies; its surface in {524}calcareous forms
is often marked by _pores_ (Fig. 239, C, _p_), which are vacuities in the
calcareous wall, closed externally by membrane. A special _median pore_
(Fig. 241, A, _m.p_) may occur, and is in some cases at least a complete
perforation through the body-wall.
The tentacles are protruded through the _orifice_, which in Cheilostomata
is usually guarded by a movable chitinous lid, or _operculum_ (Fig. 256, A,
_o_). Should the ectocyst be thickened or raised into a ridge surrounding
the orifice, a tubular passage results, known as the _secondary orifice_
(Fig. 255), at the deeper end of which is the true orifice. The _peristome_
(Fig. 255, C, _pr_) is the raised or thickened part which gives rise to the
secondary orifice. Should the zooecium be outlined by a raised ridge, the
part so enclosed is known as the _area_ (Fig. 256, C, _a_), if calcareous.
The _aperture_ or _opesia_ (Fig. 256, A, B, _ap_) is a membranous part of
the front surface; and may consist of the whole or part of the area. The
orifice or the aperture is commonly provided with _spines_ (Fig. 256, B,
_s_).
[Illustration: FIG. 257.—A, _Cribrilina annulata_ Fabr., Norway, × 33; _c_,
calcareous bars concealing the membranous aperture: B, _Membraniporella
nitida_ Johnst., Plymouth, × 45; _a_, calcareous bars growing up round the
margin of the aperture; _b_, the same, further developed; _c_, the same,
completely formed (as in A); _av_, avicularium; _o_, immature, and _o'_,
mature, ovicell; _s_, marginal spines.]
The _avicularium_ and the _vibraculum_ are specially modified zooecia (see
p. 482), which occur in a great variety of forms, in certain Cheilostomata
only. The operculum of the ordinary zooecium is represented by the
_mandible_ (Fig. 239, B, _m_) in the avicularium, and by the _seta_ (Fig.
242, _s_) in the vibraculum. The representative of the zooecium itself is
known as the _avicularian_ (Fig. 239, A, _a.z_) or _vibracular zooecium_
(Fig. 242, _v.z_).
{525}An _ovicell_ is a swelling in which the embryo develops, in certain
Cyclostomata (Fig. 237) and Cheilostomata (Fig. 241, A, _o_). A _stolon_
(Fig. 238, B, _st_) is a stem, not formed of fused zooecia, from which new
individuals originate. An _internode_, in a jointed colony, is the part
between any two joints. The _fornix_ or _scutum_ (Fig. 254, A, _f_) is a
modified spine which in some Cheilostomata overhangs the aperture. A
_mucro_ (Fig. 255, A, _mu_) is a spike or protuberance developed just below
the orifice. A _sinus_ (Fig. 239, B, _s_) is a slight bay on the lower
margin of the orifice.
The orifice opens at the _upper_ end of the zooecium, on its _front_
surface. The _length_ of the zooecium is the distance from the upper to the
lower ends, and the _width_ the distance between its sides.
{One or more of the following characters: orifice provided with an
{ operculum; avicularia or vibracula present; a globular ovicell
{ above the orifice of certain zooecia (CHEILOSTOMATA) 7
{
{Opercula, avicularia, vibracula, and ovicells completely absent,
{ or inconspicuous. Calcareous or non-calcareous. If calcareous,
1. { the orifice is not at the end of a free cylindrical portion 3
{
{Calcareous; zooecia cylindrical, often united for the greater part
{ of their length, but usually ending in a free cylindrical
{ portion,which bears the terminal orifice. The zooecia may be
{ much obscured by calcifications surrounding their basal parts 2
{Zooecia long, tubular, with a lateral membranous region at the upper
{ end, given off quite separately from a creeping stolon _Aetea_
2. {
{Zooecia more or less united to one another, orifice without
{ chitinous operculum (CYCLOSTOMATA[601]) 63
{Zooecia without marginal spines; arising from a branching axis,
{ which is not formed of zooecia 74
{
3. {Colony adherent; _or_ erect, fleshy and slightly branched; _or_
{ erect, encrusted with earthy matter and repeatedly branched 72
{
{Characters not as above 4
{Zooecia minute, boat-shaped, united by a delicate tube. Aperture
4. { large, with marginal spines _Beania mirabilis_
{
{Colony delicate, erect; zooecia wider above than below 5
{No marginal spines 6
{
5. {Zooecia uniserial; with marginal spines. Branches arising from
{ the top of a zooecium _Brettia_
{Zooecia uniserial; branches arising just below the large aperture. An
{ ovicell may be developed above the orifice of a modified zooecium
6. { _Eucratea chelata_
{
{Zooecia somewhat pear-shaped; orifice small, semicircular
{ _Huxleya fragilis_
{526}
{Colony erect 8
{
7. {Zooecia in several layers forming confused masses 30
{
{Colony entirely adherent,[602] the zooecia usually in a single
{ layer 31
ERECT CHEILOSTOMATA.
{Branches cylindrical, calcareous, divided by chitinous joints.
{ Orifices arranged all round the branc _Cellaria_ (Fig. 239, A)
{
8. {Branches flexible, jointed or unjointed. Orifices not arranged
{ all round the branch. 9
{
{Calcareous, unjointed, rigid 21
{Branches leaf-like, flattened 10
9. {
{Branches not leaf-like 11
{Avicularia resembling birds' heads, movable _Bugula_ (Fig. 233)
{
10.{Avicularia not resembling birds' heads, unstalked; _or_ absent.
{ Colony broadly leaf-shaped, composed of a single layer or of
{ two layers of zooecia _Flustra_ (Fig. 232)
{Zooecia in pairs, at the same level 12
11.{
{Zooecia not obviously paired 13
{Branches numerous, straight. Zooecia back to back, with an oblique
{ aperture. No avicularia _Gemellaria loricata_
12.{
{Branches delicate, curved. A pair of stalked avicularia between
{ each two pairs of zooecia _Notamia_ (_= Epistomia_) _bursaria_
{conspicuous 14
13. Avicularia or vibracula {
{inconspicuous or absent 17
{Avicularia resembling birds' heads, movable. Vibracula absent 15
{
{Avicularia large, unstalked. Vibracula present or absent 16
14.{
{Avicularia inconspicuous. Setae of the vibracula large, very
{ conspicuous, on oblique vibracular zooecia, which almost cover
{ the backs of the branches _Caberea_ (Fig. 242)
{Zooecia in two series, alternate, with one or several
{ conspicuously long marginal spines _Bicellaria_
15.{
{Zooecia in two or more series. Aperture occupying most of the
{ front of the zooecium. Colony often spiral. Avicularia
{ usually large _Bugula_ (Fig. 233)
{Zooecia long, narrow below, commonly in triplets, with two lateral
{ avicularia to each triplet. Fornix present. _Menipea ternata_
{
16.{Zooecia biserial, a considerable number forming an internode
{ separated by a joint (often inconspicuous) from the next
{ internode. Lateral avicularia usually large. Vibracular zooecia
{ on the back or sides of the branches _Scrupocellaria_ (Fig. 254)
{Characters as in _Scrupocellaria_ (No. 16), but with inconspicuous
17.{ avicularia. A branched fornix _Scrupocellaria reptans_
{
{Vibracula absent 18
{A single, short, marginal spine; _or_ none 19
18.{
{Marginal spines present 20
{527}
{Characters as in No. 6 _Eucratea chelata_,
{ _Huxleya fragilis_
{
{Zooecia biserial. Aperture large, the semicircular orifice at its
{ upper end, where there is commonly a short spine
{ _Cellularia peachii_
19.{
{Zooecia in one or two series. Branches originating from the backs
{ of the zooecia, and facing in the opposite direction to the
{ parent branch. Aperture small _Scruparia clavata_
{One or more conspicuously long marginal spines. Avicularia
{ present or absent _Bicellaria_
{
20.{Zooecia uniserial (see No. 5) _Brettia_
{
{Zooecia biserial, in short internodes. An inconspicuous avicularium
{ below the aperture. Fornix present _Menipea jeffreysii_
{Colony consisting of a network of narrow branches, the zooecia
{ opening only on one of their surfaces _Retepora_
{
{Colony large, brittle, composed of contorted plates, uniting
21.{ irregularly, usually composed of two layers of zooecia.
{ Orifice large, indented laterally _Lepralia foliacea_
{
{Branches delicate, cylindrical 22
{
{Branches or lobes coarser, not necessarily cylindrical 24
{Branches composed of four rows of zooecia 23
{
22.{Zooecia in more than four regular, longitudinal rows. Peristome
{ raised, and, with the ovicell, forming a swelling on the
{ surface of the branch _Escharoides quincuncialis_
{Orifice circular. A row of pores round the margin of the zooecium.
{ A median pore resembling a small orifice below the true orifice.
23.{ Small lateral avicularia _Porina borealis_
{
{Orifice surrounded by a peristome, produced into a mucro beneath
{ the orifice. No pores _Palmicellaria elegans_
{Zooecia arranged in regular series 25
{
24.{Zooecia irregularly heaped, their long axes often perpendicular
{ to the surface of the colony. Mucro largely developed,
{ concealing the form of the orifice, and bearing an avicularium
{ _Cellepora_
{Orifice with a sinus; _or_ peristome interrupted or extended below
25.{ into a sinus-like outgrowth, which usually includes a small
{ avicularium 26
{
{Neither median sinus nor interrupted or extended peristome 28
{Orifice with a sinus _Schizoporella_ (Fig. 239, B)
26.{
{Peristome interrupted or extended below 27
{Branches of various forms. Surface of the older parts very even.
{ Secondary orifice rather long, usually wider above, enclosing a
{ small avicularium below, and appearing as a hole in the even
{ surface of the branch _Porella_ (Fig. 255, B, C)
{
27.{A prominent tooth projects into the orifice from its lower side.
{ Zooecia with thin walls _Smittia landsborovii_ (Fig. 239, C)
{
{No tooth in the orifice, at the side of which is a small avicularium.
{ Old zooecia with thick walls. Colony composed of a short stem
{ and flattened branches _Escharoides rosacea_
{A tooth projects from the lower side into the large, {528}
{ subcircular orifice, on each side of which is a small oval
28.{ avicularium (colony erect or encrusting) _Mucronella pavonella_
{
{No tooth: mucro sometimes present 29
{Branches cylindrical. Old zooecia with thick walls. Orifice in
{ young zooecia longer than broad; beneath it a median pore,
29.{ and in some cases a lateral avicularium with vibraculoid mandible
{ _Diporula verrucosa_
{A distinct mucro, which may bear an avicularium above
{ _Palmicellaria_
ENCRUSTING CHEILOSTOMATA.
{Usually growing on a small univalve shell. Orifice longer than
{ broad, indented laterally. Mucro present _Lepralia edax_
{
30.{One or two conspicuous processes, each bearing an avicularium,
{ near the orifice, which is often concealed. Avicularia in many
{ cases found on other parts of the colony _Cellepora_
{Zooecia distant; _or_ in single rows 32
31.{
{Zooecia forming continuous expansions 36
{An oval aperture, larger than the orifice 33
32.{
{No aperture 34
{A tubular process below the aperture, in some cases: zooecia very
33.{ narrow below _Eucratea chelata_, var. _repens_
{
{No tubular process below the aperture _Membranipora_
{Peristome much raised below, collar-like _Phylactella_
34.{
{Peristome not much raised below 35
{Zooecia minute, much narrowed below. Orifice small, usually with
35.{ a sinus _Hippothoa_
{
{Zooecia not narrowed below. Orifice with a sinus _Schizoporella_
{Zooecia partly separated by a thin calcareous crust. Colonies
36.{ small 37
{
{Zooecia contiguous 38
{Zooecia pear-shaped. Orifice with a sinus _Hippothoa expansa_
{
37.{Zooecia ovoid. Orifice subcircular, with a tubular peristome
{ _Lagenipora socialis_
{Orifice close to the upper end of the zooecium (unless crowned by an
{ ovicell). Front of the zooecium marked by transverse or
{ radiating furrows or lines. The very young zooecium may
38.{ possess a membranous area, which becomes roofed in by the
{ union of two lateral series of converging bars (Fig. 257) 39
{
{Characters not as above 40
{Furrows with uniserial rows of pores (often minute), which are rarely
{ irregular _Cribrilina_ (Fig. 257, A)
39.{No rows of pores. Distinct transverse lines or spaces and a
{ median longitudinal suture between the bars
{ _Membraniporella_ (Fig. 257, B)
{529}
{Zooecia arranged in regular series 41
40.{
{Zooecia irregularly[603] heaped together (cf. No. 30) _Cellepora_
{Primary orifice conspicuous; with a sinus, or with a peristome
{ extended or interrupted below, and sometimes simulating a
{ sinus 42
{
{Neither sinus[604] nor interrupted peristome 44
41.{
{Surface of the old zooecia much thickened, so that the secondary
{ orifice does not project beyond the most prominent parts of the
{ zooecium. Secondary orifice concealing the primary orifice,
{ wider above, enclosing a small avicularium below
{ _Porella_ (Fig. 255, B, C)
{Primary orifice with a sinus, but no tooth 43
{
42.{A prominent tooth projects into the orifice from its lower side.
{ Peristome interrupted or with a sinus. Surface of the old
{ zooecia not much thickened _Smittia_
{Orifice with a sinus and long spines. Peristome interrupted. Ovicell
{ with a wedge-shaped or linear longitudinal fissure. Avicularia
{ generally present, the avicularian zooecium conspicuous.
{ _Schizotheca_
{
43.{Orifice semicircular. Vibracula present, near the orifice.
{ _Mastigophora_ (Fig. 241, B)
{
{Orifice semicircular or subcircular. No vibracula; avicularia with
{ vibraculoid mandibles may occur _Schizoporella_ (Fig. 239, B)
{Zooecium with a median pore; _or_ completely tubular above 45
{
44.{Zooecium with no median pore. The orifice may be partially
{ surrounded by a collar-like development of the peristome,
{ but it is not completely tubular 49
{Orifice not tubular. A median pore _Microporella_ (Fig. 241, A)
45.{
{Orifice tubular 46
{Zooecia narrow or small 47
46.{
{Zooecia ovoid 48
{Orifice markedly tubular. Median pore conspicuous _Porina tubulosa_
{
47.{Colony very small. Zooecia irregularly arranged, with no median
{ pore _Celleporella_
{Zooecia very convex, with a granular surface; ovicells set far
{ back. Orifice wider than long _Mucronella microstoma_
{
48.{Young zooecia with stellate pores. A minute avicularium, or merely
{ a pore, on the upper and lower sides of the orifice in some
{ zooecia. _Anarthropora monodon_
{Front of zooecium with an elevated margin, enclosing an area 50
49.{
{Area not present 55
{Front wall wholly calcareous 51
50.{
{Front wall wholly or partly membranous 54
{Avicularian or vibracular zooecia replacing an ordinary {530}
{ zooecium, or at least situated between the zooecia 52
51.{
{Avicularia and vibracula absent, or if present not replacing a
{ zooecium 53
{Vibracula present. Colonies small. A pair of longitudinal slits
{ within the area _Setosella vulnerata_
52.{
{Very large avicularia present. Ovicell closed by a movable lid.
{ Orifice subcircular, with a minute lateral tooth on each side.
{ _Thalamoporella_[605] (_Steganoporella_) _smittii_
{Orifice semicircular, quite at the upper end of the zooecium; usually
{ with a knob on each side _Micropora coriacea_[606] (Fig. 256, C)
53.{
{A transverse chitinous plate lies immediately below the operculum.
{ A vibraculoid spine may occur _Megapora ringens_
{Area entirely membranous, usually bordered by spines.
{ _Membranipora_ (including _Electra_[607]) (Fig. 256, A)
54.{
{Membranous portion reduced to a small portion, which may be
{ variously lobed, enclosing the orifice.
{ _Membranipora_ (other species) (Fig. 256, B)
{Peristome present. No mucro 56
{
55.{Peristome absent; _or_ if present, with a mucro 57
{
{See also _Mucronella pavonella_, No. 28).
{Peristome collar-like, much raised below and at the sides of the
{ orifice, deficient above. No avicularia _Phylactella_
56.{
{Orifice large, longer than broad. Peristome not deficient above
{ the orifice _Lepralia_
{Wall of zooecium thin, shiny, and without pores 58
57.{
{Not agreeing with the characters given under No. 58 59
{A minute avicularium above the orifice, or where an ovicell is
{ present, situated at the summit of that structure. Zooecia not
{ quite contiguous. Mucro sometimes present.
58.{ _Chorizopora brongniartii_
{
{No avicularia. Ovicells on rudimentary zooecia, lying in a plane
{ superficial to that of the rest of the colony. Zooecia long.
{ _Schizoporella hyalina_
{A more or less distinct mucro or prominence beneath the orifice. 60
{
59.{Mucro rarely present. Orifice nearly always longer than broad, or
{ nearly circular, usually large, and slightly indented laterally.
{ _Lepralia_
{A tooth projects into the orifice from its lower side 61
60.{
{No tooth 62
{Colony glistening. Orifice much obscured by the mucro and by {531}
{ stout spines developed from the peristome. Tooth (concealed in
{ old zooecia) large, strongly curved to one side.
61.{ _Rhynchopora_ (_Rhynchozoon_[608]) _bispinosa_
{
{Tooth of the lower margin of the orifice symmetrical, sometimes
{ bifid. Avicularia may be present laterally, but are not
{ developed on the mucro _Mucronella_ (Fig. 255, A)
{Orifice at least half the width of the zooecium, bordered below by a
{ well-developed prominence or "umbo." Surface of the zooecium
62.{ strongly areolated round the margin _Umbonula_[609]
{
{Orifice considerably less than half the width of the zooecium.
{ _Schizoporella_ (Fig. 239, B)
CYCLOSTOMATA.
{Colony erect. Branches of two or one series of zooecia, divided at
{ intervals by chitinous joints. Ovicells pear-shaped.
63.{ _Crisia_ (Fig. 237)
{
{Colony erect, unjointed 69
{
{Colony in the main adherent; _or_ circular; _or_ lobed 64
{Colony more or less circular, discoidal or cup-shaped, sometimes
64.{ forming secondary colonies by marginal budding 65
{
{Colonies not circular 68
{Zooecia separated by calcified interspaces, which may contain large
{ pores, often difficult to distinguish from the orifices 66
65.{
{No large pores as above. Orifices not spiny. Zooecia nearly always
{ contiguous, except where an ovicell is developed 67
{Colony composed of one or more convex discs, bearing radial ridges,
{ each composed of many zooecia _Domopora_
{
66.{Colony encircled by a thin calcareous lamina, which gives rise to
{ new zooecia, its centre usually devoid of zooecia when adult,
{ and often bearing the orifice(s) of the ovicell. Zooecial
{ orifices often spiny. _Lichenopora_
{Zooecia with a long, tubular, free portion, in some cases curved
{ in a horizontal plane. Colony fan-shaped until a late stage.
{ _Tubulipora flabellaris_
67.{
{Tubular portion absent, or for the most part curved in a vertical
{ plane. Some of the orifices may be closed by a calcareous
{ plate. Colony circular or bluntly lobed _Diastopora_
{Zooecia in one or few series, forming a linear or branched {532}
{ colony, which is closely adherent, but may give rise to short
{ erect portions. Branches narrow, but often broadening at their
{ ends. Zooecia usually with a free upper end _Stomatopora_
{
68.{Colony broadly lobed, some of the zooecia in transverse or oblique
{ ridges composed of contiguous zooecia, arranged like a row of
{ organ-pipes _Idmonea serpens_
{
{Colony broadly lobed, or fan-shaped; zooecia in many series, which
{ are not arranged like organ-pipes _Tubulipora_
{Well branched. Orifices confined to one surface of the colony 70
69.{
{Not much branched 71
{Zooecia in transverse rows, their upper ends united in the manner
{ of a row of organ-pipes. Ovicell (when present) an inflation
70.{ of the front of the branch _Idmonea atlantica_
{
{Zooecia not in regular transverse rows. Ovicell (when present) large,
{ mostly on the back of the branch _Hornera_
{Branches cylindrical, their ends massive and raised into radial
{ ridges, which carry the orifices _Domopora stellata_
71.{
{Ends of zooecia tubular, arranged all round the branch.
{ _Entalophora_
CTENOSTOMATA.
{Colony entirely adherent, or forming thick, soft, erect lobes 73
72.{
{Colony erect, well-branched, dark and opaque, resembling seaweed.
{ Zooecia with a long tubular free portion _Anguinella palmata_
{Orifice large, with two distinct lips. A variable number of stout,
{ brown spines. Encrusting _Flustrella hispida_
{
{Orifice small, rounded, borne by a more or less distinct papilla.
73.{ Encrusting or erect. Zooecia crowded, rarely in single lines.
{ _Alcyonidium_
{
{Orifice small, rounded. Zooecia widely separated, connected by
{ narrow tubes _Arachnidium_
{Axis of colony erect, usually branched 75
74.{
{Axis creeping 79
{Zooecia in elongated clusters, which occur at intervals 76
75.{
{Zooecia not grouped; _or_ in irregular groups; _or_ in whorls 78
{Zooecia regularly biserial 77
76.{
{Zooecia long, less regularly arranged. Polypide with a gizzard.
{ _Bowerbankia_ (Fig. 238)
{Clusters of zooecia very regular, occurring immediately below a
{ bifurcation of the axis. Zooecium with a broad base, not
77.{ movable. _Amathia lendigera_
{
{Zooecia arranged like the pinnules of a leaf, with a constricted
{ base, and movable on the branch _Mimosella gracilis_
{Main stem zigzag. Branchlets delicate, many ending in sharp {533}
{ points. Zooecia small, ovoid _Vesicularia spinosa_
{
78.{Axis jointed. Zooecia small, in small clusters. Polypide without a
{ gizzard _Valkeria uva_, var. _cuscuta_
{
{Zooecia in whorls, attached to the axis by thread-like stalks,
{ much longer than themselves _Hippuraria egertoni_
{Zooecia pear-shaped, produced at the lower end into a distinct
{ stalk. Gizzard absent 80
79.{
{Zooecia not distinctly stalked, although sometimes constricted
{ at the base 81
{Stalk long. Zooecium movable on its stalk, compressed, with a
{ membranous area on one side. Twelve or more tentacles.
{ Usually found on Crustacea _Triticella_
{
80.{Stalk variable. Zooecium very transparent; orifice bilabiate. Ten
{ to sixteen tentacles _Farrella repens_
{
{Zooecium very small, much elongated and narrow. Eight tentacles.
{ _Valkeria tremula_
{(See also _Arachnidium_, No. 73).
{Zooecia short, minute, with a few short spines on each side of
81.{ its broadened base. Upper end tubular _Buskia nitens_
{
{Zooecia elongated 82
{Zooecia transparent 84
82.{
{Zooecia brown, often quite opaque 83
{Zooecia large (about 1/16 inch long), distant, constricted at the
{ base, bearing scattered bristles. Usually found on Crabs or
83.{ Hydroids. _Avenella fusca_
{
{Zooecia tall, cylindrical, not constricted at the base.
{ _Cylindroecium_
{Zooecia minute. Axis dilating at intervals into swellings, from
{ which new zooecia originate. These may give rise to new
84.{ stolons,or directly to new zooecia. No gizzard. Found in
{ brackish or fresh water _Victorella pavida_
{
{Axis not dilated, as above 85
{Zooecia small, in small groups. No gizzard _Valkeria uva_
85.{
{Zooecia long, scattered or in groups. Gizzard present.
{ _Bowerbankia_ (creeping forms)
It is highly probable that the Ctenostome genus _Hypophorella_[610] will
before long be added to the British Fauna. The animal consists of delicate
stolons, which give off small zooecia at intervals; and it is known to
excavate passages in the substance of the tubes of certain Polychaet worms
(_Chaetopterus_ and _Lanice_).
{534}ADDENDUM TO CHAETOGNATHA
Since the Chapter on the Chaetognatha was printed the following list[611]
of "The Known Chaetognaths of American Waters" has appeared:—
1. _Sagitta elegans_ Verr. This species resembles _S. bipunctata_ (_vide_
pp. 191 and 193), but differs in size, in the relative proportions of
caudal and body segments, and in the presence of diverticula from the
intestine.
2. _Sagitta flaccida_ Con. This species resembles _S. hexaptera_ (_vide_
p. 193); it is, however, smaller (length, 1.3-1.8 cm.) and has more
spines (anterior, 7-8, posterior, 10-12), and its tail segment is
relatively smaller.
3. _Sagitta tenuis_ Con. Length, 5.25 mm.; hooks, 7-8; anterior spines,
4-5; posterior spines, 7-10.
4. _Sagitta hispida_[612] Con. Length, 7-11 mm.; hooks, 8-9; anterior
spines, 4-5; posterior spines, 8-15; tail segment one-third body length;
intestine with two diverticula; sensory hairs very numerous.
5. _Sagitta hexaptera_ (_vide_ p. 193).
6. _Krohnia hamata_ (_vide_ p. 194).
7. _Spadella maxima_ Con. Length, 5.2 cm.; hooks, 6; anterior spines,
3-5; posterior spines, 5-7; epidermal thickenings round the neck.
8. _Spadella draco_ (_vide_ p. 194).
9. _Spadella schizoptera_[612] Con. An opaque, yellowish-brown species
living among algae. Length, 4 mm.; hooks, 8; anterior spines, 4-6;
posterior spines wanting. Caudal segment occupies one-half the body
length.
Professor Verrill states that the name _S. gracilis_ (_vide_ p. 191) was
due to a clerical error, the species really referred to being _S. elegans._
A. E. S.
{535}CHAPTER INDEX
Every reference is to the page: words in italics are names of genera or
species; figures in italics indicate that the reference relates to
systematic position; figures in thick type refer to an illustration; f. =
and in following page or pages; n. = note.
_Acanella_, as host, 298
_Acanthobdella_, 395
Acanthocephala, 123, 124, 174 f.;
embryology, 179;
classification, 181
_Acanthocotyle_, _73_
Acanthodrilidae, 357, 362, 381, 383, _384_
_Acanthodrilus_, 356, 363, 366, 372, 382, _384_;
chaetae, 350
_Acanthozoon_, 20
Accessory gut, of Polychaeta, 305
_Aceros_, _19_
Achaeta, 445
_Acholoe_, 297
Aciculum, 247; fossil, 302
_Acmostoma_, _50_
Acoela, 42;
occurrence and habits, 43;
reproduction, 47;
classification, 49
Acotylea, 16 f., 17, 18
_Acrorhynchus_, _49_;
occurrence, 44
Actinotrocha larva, 458
_Actinurus_, 201, _222_
_Acyclus_, _221_
Adaptation, of Trematodes, 52, 62;
of Cestodes, 74;
of Nematodes, 161
Adherent, 523
_Adineta_, 204, _222_, 227
Adventitious avicularia, 482
_Aeolosoma_, 349, 353, 354, 360, 370, 374, _375_
_Aetea_, _518_, 525
Agassiz, on Syllidae, 280
_Alaurina claparedii_, _49_
_Albertia_, 204, 210, 213, _224_, 227
_Alciope_, _315_
Alciopids (Alciopina), _314_;
head, 263;
parapodium, 265;
habit, 291;
light-organs, 294
_Alciopina parasitica_, 298
_Alcyonella_, 494, 505, _518_
Alcyonellea, _518_
_Alcyonidium_, 477, 480, 492, _518_, 532;
structure of zooecium, 469;
reproduction, 507, 508;
larva, 510, 511
Alimentary canal—see Digestive System
_Alitta_, 317
_Allantonema_, 131, _150_, 151, 161
Allman, on Polyzoa, 474, 475
Alloeocoela, 43; habits, 46;
reproduction, 47;
classification, 50
Alloiogenesis, 66 n.
_Allolobophora_, 351, 367, 369, 371, 386, 389, _390_ f.;
cocoons, 365
_Allostoma pallidum_, _50_
_Alluroides_, _379_
_Allurus_, 351, 366, 370, 389;
cocoons, 365
_Alma_, 352 f., 387
Alternation of generations, 66, 81, 281
_Amathia_, 481, _518_, 532
Ammocharidae, _258_, _325_
_Ammotrypane_, 273, _331_;
intestine, 271
_Ampharete_, _330_
Ampharetidae, _258_, _330_
Amphibia, Trematodes of, 55, 62, 71, 72;
Nematodes of, 163
_Amphichaeta_, _377_
_Amphicoerus_, _49_
_Amphicora_, 339
_Amphicorine_, gill, 261
Amphicorinidae, _258_, _339_
_Amphicteis_, _330_
Amphictenidae, _258_, _330_
_Amphiglena_, 273, _339_
_Amphileptus_, 235
_Amphilina_, _91_
_Amphinome_, eye of, 255;
_A. smaragdina_, colour, 293
Amphinomidae, _258_, _318_;
shape, 259;
caruncle, 260, 273 n.;
head, 262, 263;
parapodium, 264;
cirri, 265;
chaetae, 267, 267;
in _Lepas_, 297
_Amphiporus_, 102, 114;
British species, _110_
_Amphiptyches_, 77
Amphistomatidae, _73_ {536}
_Amphistomum_, 71, _73_;
_A. hominis_, 63
_Amphitrite_, 327, _328_;
gill, 329
_Ampullaria_, _Temnocephala_ with, 53
_Anachaeta_, 350, _376_, 395
Anal, cirri, 259;
funnel, 259, 332, 333;
vesicles, 358, 436
Anangian worms, 253
_Anarthropora_, 529
_Ancylostomum_, 143, 163
Andrews, on _Sipunculus_, 417, 426
_Angiostomum_, 134
Angler-fish, Trematodes of, 62, 72
_Anguillula aceti_, 125, _154_;
_A. tritici_, 125;
_A. diplogaster_, 155
Anguillulidae, 137, _154_
_Anguinella_, 532
_Annadrilus_, _386_
Annelida, 241
_Anocelis_, _42_
Anonymidae, _19_
_Anonymus_, 16, 18, _19_, 20;
penes, 27
Anopla, 109
_Anoplocephala_, _91_;
characters, 90:
_A. mamillana_, 90;
_A. perfoliata_, life-history, 83;
specific characters, 90:
_A. plicata_, specific characters, 90
_Anoplodiscus_, _73_
_Anoplodium_, _50_;
_A. parasiticum_, occurrence, 45
_Antaeus_, 388
_Antedon_, as host, 342
Antenna, of Rotifers, 215
_Anthobothrium_, 76 n., _91_
_Anthocotyle_, _73_
_Antinoë_, 298
_Antipathes_, as host, 298
_Anuraea_, _225_, 226
Anuraeidae, 201, 205, _225_, 226
A'oon, an edible worm, 297
Apel, on Priapuloidea, 433
Aperture, of zooecium, 468, 517, 523, 524
Aphaneura, 353, _374_
_Aphanostoma_, _49_
Aphanostomatidae, _49_
_Aphelenchus_, 131, _155_, 157
_Aphrodite_, _312_;
shape, 258;
head, 260;
peristomium, 263;
chaetae, 268;
felting, 312;
intestine, 271;
genital cells, 273;
colour, 291:
_A. aculeata_, 312;
distribution, 299;
_A. echidna_, 299
Aphroditidae, _258_, _309_;
frontal ridge, 260;
parapodium, 264;
elytra, 266, 309;
chaetae, 266
Apical plate, of Trochosphere, 245
Apodina, _235_
_Apodoides_, _225_
_Apogon_, _Scolex polymorphus_ in, 77
Apsilidae, 201, 203, 214, 220, _221_
_Apsilus_, 201, 212, 213, 214, _221_
_Arabellites_, 302
_Arachnidium_, 532
Archiannelida, _241_;
anatomy, 243 f.;
nerve cords, 255;
development, 243, 245
_Archigetes_, 5, 74, 76, _91_;
significance of, 77
Area, of zooecium, 523, 524
_Arenicola_, _333_;
perienteric sinus, 252;
nephridium, 253, 254, 269;
prostomium, 259;
body, 259;
head, 264;
gill, 265;
chaetae, 266 f.;
genital organs, 273;
otocyst, 273;
burrows, 285;
pigment, 291;
colour, 293;
_A. marina_, 333;
habits, 301;
in brackish water, 284;
as bait, 297;
eggs, 314
Arenicolidae, _258_, _333_
_Argilophilus_, 372
Arhynchidae, _185_
_Arhynchus hemignathi_, 181, _185_
_Aricia_, otocyst, 273;
eggs, 275
Ariciidae, _258_, _321_;
gill, 265
Aristotle, on Earthworms, 347
Armata, 445, 446
Arthropoda, absence of cilia in, 124
Articulata, _517_, _518_
Ascaridae, 131, _138_, 163
_Ascaris_, _139_, 163;
_A. acus_, 130;
_A. alata_, 140;
_A. depressa_, 141;
_A. ferox_, 141;
_A. incurva_, 141;
_A. leptoptera_, 141;
_A. lumbricoides_, 125, 134, 135, 139, 163;
_A. megalocephala_, 125, 127, 128, 131, 136, 140, 163;
_A. mucronata_, 141;
_A. mystax_, 125, 130, 140;
_A. nigrovenosa_, 155;
_A. rubicunda_, 141;
_A. suillae_, _139_;
_A. sulcata_, 141;
_A. transfuga_, 125, 126, 141
_Ascodictyon_, 521 n.
_Ascomorpha_, _223_
_Ascopodaria_, 488 n.
_Asellus_, Rotifers attached to, 227
Asexual reproduction, in Triclads, 40;
in Rhabdocoels, 44;
in Cestodes, 80;
in _Trichoplax_ and _Salinella_, 96;
in Polychaeta, 278 f., 279, 280, 282, 340;
in Oligochaeta, 374, 375, 377;
in Polyzoa, 496, 514
Aspidobothridae, _73_
_Aspidocotyle_, _73_
Aspidocotylea, _73_
_Aspidogaster_, 63, _73_
_Aspidosiphon_, 421, 423, 424, _425_, 428;
commensalism of, 429
_Asplanchna_, 200, 205, 210, 213, 215 n., _223_, 226
Asplanchnaceae, 203, 212, _220_, _222_
Asplanchnidae, 200, 201, 203, 205, 211, 212, 216, _223_, 226, 230
_Asplanchnopus_, 201, 211, 222, _223_, 226, 230
Ass, parasites of, 140
Association, of Rhabdocoels with Lamellibranchs and Sea-urchins, 45;
of _Monotus fuscus_ with littoral animals, 46;
significance, in Turbellaria, 51—see also Commensal and Parasitic
Asteroids, as hosts, 341 {537}
_Asterope_, _315_
_Astropecten_, as host, 297, 309
Atokous phase, 277 n.
_Atractonema_, 131, _150_, 152, 153
Atrium (genital), in _Planaria_, 38, 39;
in Oligochaeta, 361, 378
_Atrochus_, 201, 213, 214, _221_
Auditory organs, of Turbellaria, 26;
of Hoplonemertea, 106, 110;
of Nematoda, 128;
of Polychaeta, 273
_Aulastomum_, 393, 399, 403
Auricles, of Rotifers, 205
_Autolytus_, _308_;
eye, 255;
denticles, 270;
brood-sac, 275, 276;
reproduction, 278, 279;
sexual dimorphism, 281;
_A. ebiensis_, eggs, 276
_Automolos_, British species, _50_
_Avenella_, 533
Avicularian zooecium, 482, 524
Avicularium, 466, 467, 468, 482 f., 482, 516, 517, 522 f., 524;
adventitious, 482;
vicarious, 482;
vibraculoid, 484, 485;
structure, 483;
movements, 485;
function, 486
_Axine_, 56, _73_
_Axiothea_, _332_, 333
Baely, on human parasites, 139
Baird, on Oligochaeta, 382
Bait, Polychaeta as, 297
Baker, on Rotifers, 197, 207; on Polyzoa,
496 n.
_Balanoglossus_, affinities of Nemertinea with, 120
_Balatro_, 204, 212, _224_, 227
Balfour, on Trochosphere, 229
_Barentsia_, 488 n.
Barrois, on Polyzoa, 509
Basement-membrane, of _Leptoplana_, 11, 12;
of Nemertines, 102, 103, 110 f.
Bathymetrical distribution, of Polychaeta, 300
_Bdellodrilus_, _376_
Bdelloida, 201, 203 f., 211, 213, 215, 216, _222_, 227
Bdellouridae, 32, _42_
_Beania_, _518_, 525
Beddard, on _Tetrastemma aquarium dulcium_, 118;
on Oligochaeta, 347 f.;
on Leeches, 392 f.
Bedwell, on Rotifers, 198
Beneden, van, on Cestodes, 76;
on Nematodes, 162;
on _Phoronis_, 450
Benham, on a fresh-water _Tetrastemma_, 118;
on Archiannelida, 241 f.;
on Polychaeta, 245 f.;
on Myzostomaria, 341 f.;
on Oligochaeta, 357, 373, 382;
on _Phoronis_, 452 f.
_Benhamia_, _383_ f.
_Bicellaria_, 481, _518_, 526, 527
Bilfinger, on Rotifers, 212
_Bilharzia_, 4, _73_;
_B. crassa_, 70;
_B. haematobia_, 63, 68 f., 69
_Bimastos_, _389_
Bipaliidae, 35, _42_
_Bipalium_, 33, 34, _42_, 408
Birds, Trematodes of, 62, 63, 64, 72;
Cestodes of, 77 f., 84, 85;
Nematodes of, 144, 149, 163;
_Gordius_ of, 173;
Acanthocephala of, 184, 185
Bisexual, Turbellaria, 44;
Trematodes, 70 f.
Bladder, of Rotifers, 214
Bladder-worms, 5, 79 f., 89
Blanchard, on Cestoda, 91;
on Hirudinea, 392 f., 405, 408
Blastomeres, of egg of _Distomum_, 65
Blood, of Nemertinea, 108;
of _Polygordius_, 244;
of Chaetopoda, 252;
of Chlorhaemidae, 252, 334;
of _Magelona_, 252, 325;
of Sabelliformia, 252, 337
Blood-corpuscles, in Chaetopoda, 252
Body-cavity (including Coelom), of Nematoda, 130;
of _Gordius_, 166;
of Acanthocephala, 175, 178;
of Chaetognatha, 187;
of Archiannelids, 243, 244;
of Polychaeta, 249;
of _Myzostoma_, 343;
of Oligochaeta, 355;
of Leeches, 397;
of Gephyrea, 416;
of _Phoronis_, 454, 462;
of Polyzoa, 468, 488, 495
Body-wall, of Nemertinea, 102, 103;
of Nematodes, 125;
of Gordiidae, 165;
of Acanthocephala, 175;
of Chaetognatha, 187;
of Rotifers, 205;
of _Nereis_, 249;
of Oligochaeta, 349;
of Gephyrea, 414, 436;
of _Phoronis_, 454;
of Polyzoa, 470, 495, 500
Bohadsch, on Gephyrea, 411
_Bohemilla_, _377_;
chaeta, 350
Bonellein, 435, 292
_Bonellia_, 411, 434, _442_;
anatomy, 434 f., 435;
male, 438;
development, 439;
habits of, 442;
as host, 297
Bonnet, on Oligochaeta, 348, 379
Boring Worms, 286, 287
Borlase, on _Lineus marinus_, 99
_Borlasia elizabethae_, _111_, 114
Bothriocephalidae, _91_
Bothriocephalinae, _91_
_Bothriocephalus_, _91_;
_B. cordatus_, 81, 91;
_B. cristatus_, 81, 91;
_B. latus_, in man, 81, 91;
life-history, 84;
reproductive organs, 87 f.;
larva, 87;
_B. mansoni_ (= _B. liguloides_), 81, 91
_Bothriocerca_, 226
_Bothrioneuron_, _379_
_Bothrioplana_, 46, _50_
Bothrioplanidae, 42, 46, _50_
_Bothromesostoma personatum_, _49_
Bourne, on Oligochaeta, 352, 373, 377 n., 380;
on Leeches, 400
Bouvier, on commensal Gephyrea, 429
_Bowerbankia_, 470, 480, 481, 492, 500, _518_, 532, 533; {538}
larva, 511, 513;
budding, 514
Brachionidae, _225_
_Brachionus_, 200, 201, 204, 218, _225_, 226, 227
_Brachydrilus_, 357
Brackish water, Rotifers, 226;
Polychaeta, 284;
Polyzoa, 492
_Bradynema_, _150_, 151, 160
Braem, on statoblasts, 503 f.
Brain—see Nervous System
_Branchellion_, 393, 395, 397, 401, _406_
Branchial crown, 336;
regeneration of, 283
_Branchiobdella_, _376_
_Branchiomma_, _337_;
gills, 261;
eyes, 272;
_B. vigilans_ on _Aphrodite_, 299
_Branchiura_, 352, 361, 367, _378_ f.;
transverse section, 353
Braun, on Platyhelminthes, etc., 6 n., 55 n., 62, 94
_Brettia_, 525, 527
Bristles = Chaetae, _q.v._
Bristle-worms, 241
British, Polycladida, 19;
Tricladida, 42;
Rhabdocoelida, 49;
Nemertinea, 100, 110 f.;
Polychaeta, 306 f.;
Earthworms, 390;
Leeches, 393;
Gephyrea, 449;
Polyzoa, 488 n., 505, 523 f.
Brood-pouch, of _Spirorbis_, 261, 276, 341;
of _Salmacina_, 276;
of Entoprocta, 487, 507
Brood-sac, of _Autolytus_, 275;
of _Myrianida_, 280
Brown body, in Polyzoa, 468, 471 f., 472, 489, 496, 510, 514
Brown tubes (nephridia), of Sipunculoidea, 415, 417, 423, 425;
of Echiuroidea, 435, 437, 439, 441;
of Epithetosomatoidea, 445;
used as generative ducts, 418, 438;
absent in Priapuloidea, 430
Bryozoa, 475
Buccal region, in Polychaeta, 249, 250, 269;
of _Nereis diversicolor_, 248;
of _N. cultrifera_, 316
Buchanan, on marine muds, 423
_Buchholzia_, 359
Budding, in Syllidae, 279, 283 (see also Gemmation);
in Polyzoa, 467, 514 (see also Polypide-bud)
_Bugula_, 467, 468, 477, 481, 515, 517, _518_, 519, 526;
avicularia, 483, 485;
larva, 511
Bunge, on respiration in Nematoda, 130
Bürger, on Nemertinea, 109, 112;
on _Nectonema_, 168;
on Hirudinea, 397, 403
Burrows, of Polychaeta, 285, 304;
of _Cirratulus_, 286;
of _Nereis_, 286, 316, 317;
of _Arenicola_, 333;
fossil, 302;
of Earthworms, 368;
of _Sipunculus_, 426
Bursa seminalis, in Rhabdocoels, 48
Busk, on Polyzoa, 465 n., 475, 487, 519
_Buskia_, 533
Bütschli, on Nematoda, 137
_Byrsophlebs_, occurrence, 44;
British species, _49_
_Caberea_, 487, _518_, 526;
vibracula, 486, 517
Caecum, in Polyzoa, 499
_Calathus_, host of _Gordius_, 172
Calceostominae, _73_
_Calceostomum_, _73_
Caldwell, on _Phoronis_, 454, 456, 461
_Calicotyle_, _73_
_Callidina_, 201, 202, 204, 218, 219, _222_, 225, 227, 230
_Calliobothrium_, 76 n., _91_;
larva, 77
Calotte, of Dicyemids, 93
Calyx, 488
Camerano, on development of _Gordius_, 170
_Capitella_, _331_;
peristomium, 263;
special chaetae, 267, 268;
habitat, 286;
colour, 291;
_O. capitata_, distribution, 299
Capitellidae, _258_, _331_, 373
Capitelliformia, _258_, _305_;
guanin in, 253;
body, 259;
buccal region, 269;
siphon, 272;
ciliated organs, 272, 273;
genital organs, 273
_Carabus_, host of _Gordius_, 172
_Carinella_, 112;
British species, _112_
Carinellidae, side organs of, 107
Caruncle, of Amphinomidae, 260, 273 n., 318
_Caryophyllaeus_, _91_;
_C. mutabilis_, 77
_Castalia_, _308_;
distribution of, 300
Castings, of Polychaeta, 285;
fossil, 302;
of _Arenicola_, 333
_Castrada_, 44, _49_
Cat, parasites of, 80, 125, 130, 140, 143, 144, 145
_Catenicella_, _518_, 519
_Catenula_, _49_
_Cathypna_, _225_
Cathypnidae, _225_
_Cellaria_, 479, 515, _518_, 519, 526;
zooecia and avicularium, 482
_Cellepora_, _518_, 527, 528, 529;
avicularia, 483, 517
_Celleporella_, 529
_Cellularia_, _518_, 527
Cellularina, _518_
Cement-glands, of Rotifers, 205
Cephalic slits, of Nemertinea, 101, 104, 107, 111, 112
Cephalisation, in Polychaeta, 263;
in Oligochaeta, 377
_Cephalodiscus_, 461 f.
Cephalopods, parasites of, 78, 92;
list of, containing Dicyemids, 94
_Cephalosiphon_, 205, _221_
_Cephalothrix_, _112
Cercaria_, 13, 65, 67, 71 f.; {539}
_C. macrocerca_, 72;
_C. cystophora_, 72
_Cercyra_, 42
Cerebral organ, of Nemertinea, 107;
of Gephyrea, 417
_Cerebratulus_, 101, 111, 114;
British species, _111_
Cerfontaine, on Earthworms, 349, 350
Cestoda, characters of the group, 5, 74;
nature of, 76 f.;
occurrence, 77-82;
life-histories, 83;
structure and development, 84-89;
synoptic table of, 89 f.;
classification, 91
Cestodariidae (= Monozoa), _91_
_Cestoplana_, 17, 18, _19_
Cestoplanidae, _19_
Chaetae, 241;
of Polychaeta, 266, 267;
provisional, 274;
of _Nereis_, 246, 247;
of Heteronereid, 276, 277;
jointed, 246;
natatory, in sexual Syllid, 278, 307;
iridescent, 268, 291, 312;
palmate, of _Coabangia_, 339 n.;
colour, 291;
genital, of _Capitella_, 331;
of _Sternaspis_, 336;
special, of _Polydora_, 261, 267;
of _Chaetopterus_, 267, 324;
of _Myzostoma_, 342;
of Oligochaeta, 347, 350, 351, 352;
penial, 362;
of Microdrili, 375 f.;
of Megadrili, 381 f.;
of Lumbricidae, 389, 390;
of Leeches, 395, 396;
(= hooks), of Echiuroid Gephyrea, 434, 435, 438, 440 f., 446
Chaetifera, 445, 446
_Chaetobranchus_, 352
_Chaetogaster_, 356, 377, 401
Chaetognatha, 186 f., 534;
anatomy, 186;
development, 189;
habits, 189;
classification, 191;
key to, 193;
American species, 534
_Chaetonotus_, 232, _235_
Chaetopoda, 241 f.;
as food for Nemertinea, 115
Chaetopteridae, 258, _323_
_Chaetopterus_, 304 n., _323_;
anatomy, 323 f.;
special chaetae, 267;
larva, 274, 325;
pigment, 292;
phosphorescence, 295, 296;
commensals of, 298, 478, 533;
_Ch. variopedatus_, 324
_Chaetosoma_, 158
Chaetosomatidae, _158_
Chaetosyllis, form of head, 278
_Chaetozone_, _326_;
uncini, 268
_Chaetura_, _235_
Chalk, Serpulids of, 301
Charles, on male guinea-worm, 148
Cheilostomata, _477_, 506, _518_, 519, 525, 526 f.;
occurrence, 478;
external characters (see also Avicularium and Vibraculum), 481;
ovicells, 507;
reproduction, 507 f.;
larva, 511;
fossil, 521
Chiaje, Delle, on Gephyrea, 411
Chickoff, on Triclads, 41
_Chironomus_, host of _Gordius_, 172
Chitin, 249, 267;
in coelomic corpuscles, 252
_Chloeia_, colour, 291
Chlorhaemidae, _258_, 305, _334_, 336;
chlorocruorin in, 252;
head, 260, 262, 264;
palps, 260;
tentacles, 262
Chlorocruorin, 252, 334;
colour due to, 291
_Chone_, _338_
_Chorizopora_, 530
Cilia, 3;
of _Leptoplana_, 10, 11, 12, 15;
of Polyclads, 23, 25, 26;
of Müller's larva, 29;
of Land Planarians, 33;
of _Planaria lactea_, 35;
of _Temnocephala_, 53;
of Trematode-larvae, 3, 59, 60, 65;
of Cestode-larvae, 87;
absent in certain groups, 124, 396;
of Rotifers, 202 f.;
of Archiannelida, 243, 244;
of Echiuroidea, 434;
of _Phoronis_, 453;
of Polyzoa, 467, 470
Ciliated, lappets, of _Pterosyllis_, 273 n.;
pits, of _Polygordius_, 244;
pits (= nuchal organs), of Polychaeta, 272 f.;
organs, of Capitelliformia, 305
Cingulum, in Rotifers, 202
Cirratulidae, _258_, _325_;
gill, 265;
tentacular filaments, 304 n.
_Cirratulus_, _326_;
burrows, 286;
pigment, 292;
colour, 293;
viviparous, 276;
_C. tentaculatus_, 326
Cirri, of _Nereis_, 246;
of Polychaeta, 265;
of _Myzostoma_, 342;
anal, 259;
nuchal, of Eunicidae, 318;
peristomial, of _Nereis_, 248;
nerves to, 254;
of Polychaeta, 263
_Cladocora_, with _Myxicola_, 294
Claparède, on Heteronereis, 276, 277;
on Earthworms, 347, 355, 356
Claus, on Nematoda, 138;
on Seisonaceae, 225 n.
_Clepsine_—see _Glossiphonia_
_Clitellio_, 366, 378
_Cloeosiphon_, 424, _425_, 429
Clover sickness, 155
_Clymene_, _333_;
_C. ebiensis_, tube of, 287
Clymenidae—see Maldanidae
_Coabangia_, 284, _339_ n.
Cobb, on Nematoda, 131 n., 138
Cobbold, on Nematoda, 140
_Cobitis_, host of _Gordius_, 173
_Cochleare_, _225_
Cocoons, of Triclads, 40;
of Oligochaeta, 364, 365;
of Leeches, 404
Coelom—see Body-cavity
Coelomic fluid, of Polychaeta, 252;
as cause of colour, 291
_Coelopus_, _225_
Cohn, on Rotifers, 198
Collar, peristomial, of Sabellidae, 336;
of Gephyrea, 421;
of Ctenostomata, 470, 477, 480, 481
Colonial nervous system, 471
Colony, of _Myrianida_, 281; {540}
of _Syllis ramosa_, 282;
of Polyzoa, 466
Colour of Polyclads, 20;
of Land Planarians, 33;
of Nemertinea, 102;
of Polychaeta, 291, 314, 340
Coluridae, 207, _225_
_Colurus_, _225_, 226
_Comatula_, as host, 342
Commensal, Polychaeta, 297 f., 323, 325;
Gephyrea, 428, 429;
Polyzoa, 489
Conn, on development of Gephyrea, 419 n., 441, 444, 447
_Conoceros_, _19_
_Conochilus_, 202, 203, 205, 215, _221_, 226
_Conocyema_, hosts of, 94
_Convoluta_, 45;
British species, 43, _49_;
_C. henseni_, pelagic habit, 43;
_C. roscoffensis_, assimilating tissue, 43
Copepoda, on Polychaeta, 299
_Copeus_, 215, _224_
Coral reefs, Polychaeta in, 293
_Corallina_ (= Coralline Alga), 14, 488, 516
Coralline, 465
Coralline Crag, 465, 521
_Corallobothrium_, _91_
_Corethra_, host of _Gordius_, 172
Cori, on _Phoronis_, 451 f.
_Cornulites_, 302
Cotylea, 16 f., 17, 18
_Cotylogaster_, _73_
_Cotyloplana_, 35
_Crateromorpha_, as host, 282
Crayfish, _Temnocephala_ associated with, 53
Creeper, 317
_Crepina_, 450
Cretaceous, Polyzoa, 520, 521
_Cribrilina_, _518_, 524, 528
Crinoids, as hosts, 341
_Criodrilus_, 358, 366, _386_
_Crisia_, 471, 478, 479, 480, 507, _518_, 531
Crisiidae, _517_
Crisp, on Parasites, 164
_Cristatella_, 494 f., 495, 499, 501, 503-505, 512, _518_;
attacked by Planarians, 486;
movements, 494, 496, 498;
fission, 496, 506;
statoblast, 502, 503;
larva, 512
_Crossopodia_, 302
Crotchets, 266, 267, 305, 322
Crustacea, parasites of, 174, 179, 182
_Cryptocelis_, _19_, 24
Cryptocephala, _258_, _303_, _305_;
vascular system, 252;
prostomium, 259;
tentacles, 263;
eyes, 272;
food, 296
Cryptodrilidae, 357, 362, 373, _382_
_Cryptodrilus_, 372, _382_ f.
_Ctenodrilus_, 373
Ctenophores, as hosts, 298
Ctenostomata, 470, _477_, 479, 480, _518_, 532;
occurrence, 478;
in fresh water, 492;
external characters, 480;
reproduction, 507;
larva, 511;
relation to Phylactolaemata, 493, 502 f.;
fossil, 521 n.
_Cucullanus_, 136, _142_, 163;
_C. elegans_, 143, 161
_Cucumaria_, as host, 298
Cuénot, on Gephyrea, 416 n.
Cuticle, of Nemathelminthes, 125, 165, 175;
of Rotifera, etc., 205, 233, 236;
of Polyzoa, 470—see also Epidermis
Cuvier, on Oligochaeta, 352;
on Gephyrea, 411
_Cyclatella_, _489_
_Cyclicobdella_, 392
_Cycloporus_, _19_, 22, 24
_Cyclops_, parasites of, 143, 148, 161
Cyclorhagae, 238
Cyclostomata, _477_, 479, 506, _517_, _518_, 525, 531;
occurrence, 478;
external characters, 480;
ovicells, 507;
reproduction, 507, 511;
larva, 511; fossil, 520, 521
_Cydippe_, as host, 298
_Cylindroecium_, 533
_Cylindrostoma_, 46;
British species, _50_
Cyphonautes, 509, 510, 512, 520
_Cyprina_, _Malacobdella_ found on, 119
_Cyrtonia_, _224_
Cyst, of Land-Planarians, 33;
of _Myzostoma_, 342, 343, 344;
(capsules), of _Aeolosoma_, 370, 375
_Cystibranchus_, 395, _406_
Cysticercoid-larva, 83, 85, 88
_Cysticercus_-larva, 79, 80;
list of, 83;
_C. cellulosae_, 79, 80;
_C. pisiformis_, development, 81, 85, 89
Cysticolous, Myzostomaria, 344
Cystoidotaeninae, _91_
Cystotaeninae, _91_
_Dactylogyrus_, _73_
Dalyell, on habits of Turbellaria, 6, 10, 20;
on regeneration in Polychaeta, 283;
on tubes of Polychaeta, 287;
on Hirudinea, 405 n.;
on larvae of _Flustra_, 466;
on _Cristatella_, 496
Danielssen and Koren, on Gephyrea, 442, 444
_Daphnia_, Rotifers attached to, 227
_Dapidia_, _225_
Darwin, on Earthworms, 354, 359, 368
_Dasybranchus_, _331_;
gill, 268
_Dasychone_, _338_;
gills, 261;
eyes, 272;
regeneration, 283
_Dasydetes_, 232, _235_
Davaine, on Nematoda, 140, 145
_Davainea_, _91_;
_D. friedbergeri_, 84;
_D. madagascariensis_, 80, 84;
_D. proglottina_, life-history, 84
Davenport, on _Urnatella_, 491
Davis, on Rotifers, 227
Deep-sea, Polychaeta, 300;
Polyzoa, 478
_Deinodrilus_, 351, _384_
_Delagia_, 478 n.
_Dendrobaena_, _382_ {541}
_Dendrocoelum_, 30, 35, 39
_Dendrostoma_, 422, _425_, 428
Dendy, on Land Planarians, 33, 34, 38
Denticles, 248, 250, 316, 522
_Dero_, 352, _377_
_Derostoma_, 44, _50_
_Desmogaster_, _380_
Desmoscolecidae, 159
_Desmoscolex_, 159, 258
Desor, on Nemertine development, 99;
Type of, larva, 113
Development, of Polyclads, 28;
of Nemertinea, 99, 113;
of Nematoda, 135;
of _Gordius_, 171;
of Acanthocephala, 179;
of Chaetognatha, 189;
of Rotifers, 218;
of Archiannelida, 243, 245;
of Polychaeta, 274 f.;
of Oligochaeta, 365;
of Leeches, 399;
of Gephyrea, 419, 432, 439, 447;
of _Phoronis_, 458;
of Polyzoa, 506, 509—see also Life-history and Larva
_Diachaeta_, 366
Diaphragm, of _Nereis_ introvert, 250, 251;
of Terebellidae, 304, 327;
of Polyzoa, 469, 470, 500, 508
_Diaschiza_, _225_, 226
_Diastopora_, _518_, 531
_Dichogaster_, 362, _383_
_Diclidophora_, _73_
_Dicotylus_, 32, 35, 36, _42_
_Dicranotaenia_, _91_;
_D. coronula_, life-history, 84
_Dicyema_, 93;
vermiform larva of, 92;
hosts of, 94
_Dicyemennea_, 93, 93;
hosts of, 94
Dicyemidae, 92 f.
_Didymogaster_, _383_
_Didymozoon_, _73_;
_D. thynni_ (= _Monostomum bipartitum_), 71
Didymozoontidae, _73_
_Digaster_, 358, 359, _382_ f.
Digenea (Digenetic Trematodes), 5, 52, 62, _73_;
occurrence and habits, 62;
life-histories, 63 f., 71 f.
Digestive system, of _Leptoplana_, 11, 12;
of Polyclads, 24;
of Triclads, 37, 39;
of Rhabdocoelida, 42 f.;
of _Temnocephala_, 53, 54;
of _Polystomum_, 57;
of _Distomum_, 62;
absence of, in Cestodes, 74;
of Nemertinea, 103, 103, 104;
of Nematoda, 130;
of Gordiidae, 166, 169;
of Chaetognatha, 187;
of Rotifers, etc., 209, 233, 237;
of Archiannelida, 243;
of Polychaeta, 249, 269;
of Oligochaeta, 358;
of Hirudinea, 396;
of Gephyrea, 414;
of _Phoronis_, 454;
of Polyzoa, 468, 469, 487
_Digitibranchus_, 353
_Diglena_, 212, 217, _224_, 226
Digonopora, 16
Dimorphism, in _Polystomum_, 59;
sexual, of Trematodes, 70;
of Orthonectida, 95;
of _Dinophilus_, 243;
of Polychaeta, 276, 279 f.;
of Gephyrea, 438
Dinocharididae, _225_
_Dinocharis_, _225_
_Dinophilus_, 242;
_D. taeniatus_, 242;
_D. gyrociliatus_, sexual dimorphism, 243
_Dinops_, _223_
_Diopatra_, gill, 318
Diphyllinae, _91_
_Diplax_, _225_
_Diplectanum_, _73_
_Diplobothrium_, _73_
_Diplocardia_, _385_
_Diplodiscus_, _73_;
_D._ (_Amphistomum_) _subclavatum_, life-history, 71
_Diplogaster_, _154_
_Diplois_, _225_
_Diplostomum_, _73_
_Diplozoon_, 55, 60, _73_;
life-history, 60, 61;
reproductive organs, 60
_Diporochaeta_, _381_
_Diporpa_, 60, 61
_Diporula_, 528
_Dipylidium_, 81, _91_;
life-history, 83, 88, 89;
specific characters, 90
Disc, in Rotifers, 200, 202 f., 202
Discharge, of genital cells;
Nemertinea, 116;
Archiannelida, 244;
Polychaeta, 256, 274, 275
_Discobdella_, 226
_Discocelis_, _19_, 23
Discodrilidae, 350, _376_, 392, 395
_Discopus_, 201, _222_, 226, 227
_Dispharagus_, _147_, 149, 163
_Dispinthera_, _225_
_Distemma_, 212, _224_, 226
Distomatidae, _73_
_Distomum advena_ (= _D. migrans_), life-history, 71;
_D. appendiculatum_, life-history, 71;
_D. ascidia_, life-history, 71;
_D. atriventre_, life-history, 71;
_D. brachysomum_, life-history, 71;
_D. buskii_, 63;
_D. caudatum_, life-history, 71;
_D. clavigerum_, life-history, 72;
_D. conjunctum_, 63;
_D. crassum_, 63;
_D. cygnoides_, life-history, 72;
_D. cylindraceum_, 72;
_D. dimorphum_, 72;
_D. echinatum_, 63;
life-history, 72;
_D. echiuri_, 444;
_D. endolobum_, life-history, 72;
_D. excavatum_, 63;
_D. ferox_, 63;
_D. globiporum_, life-history, 72;
_D. hians_, 63;
_D. hepaticum_ (liver-fluke), 3, 63, 67 f.,72;
_D. heterophyes_, 63;
_D. hystrix_, life-history, 72;
_D. japonicum_ (= _D. spathulatum_), 63;
_D. lanceolatum_, 63;
_D. luteum_, excretory system of, 62;
_D. macrostomum_, life-history, 64, 65, 72;
_D. magnum_, 68;
_D. militare_, life-history, 72;
_D. nodulosum_, life-history, 72;
_D. oculi-humani_ (= _D. ophthalmobium_), 63;
_D. ovocaudatum_, life-history, 72;
_D. pulmonale_, 63, 70;
_D. rathouisi_, 63, 70;
_D. retusum_, life-history, 72;
_D. ringeri_ (= _D. pulmonale_), 63; {542}
_D. signatum_, life-history, 72;
_D. sinense_, 70; _D. spathulatum_, 63;
_D. squamula_, life-history, 72;
_D. trigonocephalum_, life-history, 72;
_D. westermanni_ (= _D. pulmonale_), 63
_Distyla_, _225_
_Dithyridium_, _91_
_Ditrupa_, 301
_Diurella_, _225_, 226
_Dochmius_, 133, 135, _142_, 160, 163;
_D. cernua_, 143;
_D. duodenalis_, 143, 163;
_D. stenocephala_, 143;
_D. trigonocephala_, 143
_Dodecaceria_, 287, _326_, 327
Dog, parasites of, 80 f., 90, 125, 140, 142, 143, 145
_Dolichoplana_, 37, _42_
Domestic animals, Trematodes of, 67, 68, 70, 72;
Cestodes of, 81, 89;
Nematodes of, 139 f., 163;
Acanthocephala of, 184
_Domopora_, 531, 532
Dorsal ciliated organ, 247, 254, 256
Dorsal pores, 348
_Dorylaimus_, 131, _157_, 160
_Dracunculus_, 131, 135, 147
_Drepanidotaenia_, _91_;
_D. anatina_, life-history, 84, 85;
_D. gracilis_, _D. infundibuliformis_, _D. setigera_, life-history, 84
_Drepanophorus_, excretory system, 108;
British species, _110_
Drilophagidae, _224_
_Drilophagus_, 204, 210, 212, _224_, 227
Dugès, on Planarians, 6, 10;
on Oligochaeta, 368
Dujardin, on Rotifers, 198;
on Gastrotricha, 231;
on Kinorhyncha, 236
Duplicature, 499, 500
_Duthiersia_, _91_
Dwarf males, of _Myzostoma_, 344;
of Gephyrea, 438
Ear-cockle, 155
Earthworms, 347, 365;
senses, 354;
food, 359;
effect on the soil, 368;
distribution, 369 f.;
classification, 380 f.;
British, 390—see also Oligochaeta
Ebrard, on Hirudinea, 393
_Echeneibothrium_, _91_
_Echinella_, _73_
_Echinobothrium_, 74, 75, 85, _91_
_Echinococcus_, 80, 83
_Echinocotyle_, _91_
_Echinoderes_, 236 f., 236
Echinorhynchidae, _182_
_Echinorhynchus acus_, 175, 179;
_E. angustatus_, 174, _183_;
_E. clavula_, _183_;
_E. haeruca_, 176;
_E. linstowi_, _183_;
_E. lutzii_, _183_;
_E. moniliformis_, _183_;
_E. proteus_, 174, 180, 181, 182, 182
_Echinosiphon_, 424, 429
Echiuroidea, 241 n., _412_, 434, 446;
anatomy, 434 f.;
classification, _440_;
development, 439;
parasites, 444;
habits, 442
_Echiurus_, 336, 411, 435, 440, _441_;
development, 439
Eckstein, on Rotifers, 198
_Eclipidrilus_, _380_
Economic uses, of Polychaeta, 296, 297
Ectocyst, 469, 470, 523;
of Phylactolaemata, 496 f., 503
Ectoderm, of Mesozoa, 93, 95
Ectoparasitic Trematodes, 4, 52, 53
Ectoprocta, _475_, _518_;
structure, 469;
lophophore, 476;
reproduction, 506 f.;
larva, 509, 510, 511;
compared with Entoprocta, 488
Effects, of parasites on their hosts, 56, 68, 69, 80, 94, 162
Eggs, of _Leptoplana_, 10, 16;
of Polyclads, 28;
of Triclads, 33, 40;
of Rhabdocoels, 47, 48;
of Termatodes, 52;
of ectoparasitic Trematodes, 54, 58, 60, 61;
of endoparasitic Trematodes, 63, 69;
of Cestodes, 87;
of Orthonectidae, 95;
of Nemertinea, 116;
of Nematoda, 135, 162;
of _Gordius_, 171;
of Acanthocephala, 179;
of Chaetognatha, 189;
of Rotifera, 200, 216 f.;
of Gastrotricha, 234;
of _Nereis_, 256;
of Polychaeta, 274, 275;
of Phyllodocids, 314;
of _Scoloplos_, 321;
of _Myzostoma_, 343;
of Polyzoa, 506, 507
Ehrenberg, on Turbellaria, 3, 6;
on Rotifers, 198, 220 n., 228;
on Gastrotricha, 231;
on Polyzoa (Bryozoa), 475
Eichhorn, on Rotifers, 197
Eisen, on Oligochaeta, 380, 390
Eisig, on Capitellidae, 373;
on _Bonellia_, 443
_Electra_, 481, _518_, 523, 530;
larva, 509, 510;
variation, 516
Elytra, of Polynoids, 265, 292, 294, 298, 299, 309, 310, 311;
phosphorescent, 295, 296;
as brood-pouch, 275;
of Aphroditidae, 266;
arrangement of, 309;
of Sigalionina, _313_
_Enantia_, 16 n., _19_
Enantiidae, _19_
_Enchelidium_, _157_
Enchytraeidae, 359, 360, 361, 366, 367, 370, _375_
_Enchytraeus_, host of _Gordius_, 173
_Encotylabe_, _73_;
eggs of _E. pagelli_, 58
Endocyst, 471
Endoderm, of Mesozoa, 93, 95
Endoparasitic Trematodes, 4, 52, 62
Enopla, 109
Enoplidae, _157_
_Enoplus_, 157, 160
_Entalophora_, _518_, 532
_Enteroploea_, _224
Enterostoma_, 46; {543}
British species, _50_
Entoprocta, _475_, 479, 487 f., _518_;
lophophore, 476;
reproduction, 506;
larva, 509, 510
_Eosphora_, 216, 218, _224_
_Ephemera_, host of _Gordius_, 172, 173
_Ephesia_, _321_
_Epibdella_, 55, _73_
Epidermis, of _Leptoplana_, 11, 12;
of Polyclads, 20, 25, 29;
of Trematodes, 56;
of Cestodes, 85;
of Nemertinea, 102;
of Nematoda, 125;
of Acanthocephala, 175;
of _Nereis_, 249;
of Oligochaeta, 349;
of Leeches, 396;
of Gephyrea, 414;
of _Phoronis_, 454—see also Hypodermis
Epigamous, phase, of _Nereis_, 277 n.;
worms, 281
Epistome, in _Phoronis_, 453, 455;
in Phylactolaemata, 476, 476, 499;
in larva of _Loxosoma_, 509
_Epistomia_, _518_, 526
_Epithetosoma_, 444, 445, 449
Epithetosomatoidea, _412_, 444
Epitokous, phase, of _Nereis_, 277 n.
_Eretmia_, _225_, 226
Eriographidae, _258_, _338_
_Erpocotyle_, _73_
Errantia, 258, 285
_Eschara_, 516
Escharina, _518_
_Escharoides_, 527
Euchlanididae, _225_
_Euchlanis_, _225_, 226
_Eucratea_, _518_, 525, 527, 528
Eudrilidae, 359, 360, 380, _385_, 403 f.
_Eudrilus_, 354, _385_, 403 f.
Euichthydina, _235_
_Eulalia viridis_, _314_;
pigment, 292;
colour, 293;
eggs, 314 n.
_Eumenia_, _334_
_Eunice_, 318, _319_;
nephridium, 254;
eye, 255;
head, 262;
parapodium, 264;
gill, 265;
chaetae, 266, 267;
jaws, 270;
substance of tube, 290;
commensal, 298;
_E. tibiana_, 290
Eunicidae, _258_, _318_;
palps, 260;
tentacles, 262;
jaws, 270;
tube, 285, 290;
colour, 291, 292;
parasitic, 297;
tubes containing Polynoids, 298;
Palaeozoic, 302
_Eunicites_, 301, 302
_Euphrosyne_, _318_;
parapodium, 265;
chaetae, 267
_Eupolia_, _113_
Eupolyzoa, 461
_Eurycercus_, shell of, inhabited by Rotifers, 227 n.
_Eurylepta_, _19_
Euryleptidae, _19_
_Eurythoe_, _318_
_Eustrongylus gigas_, _142_;
_E. tubifex_, _142_
_Eusyllis_, reproduction of, 278
Excretion, as cause of colour, 291
Excretory system, of _Leptoplana_, 13;
of Polyclads, 25;
of Triclads, 41;
absent in Acoela, 42;
of Temnocephala, 54;
of Digenea, 62;
of Cestodes, 86;
of Nemertinea, 108, 108, 120;
of Nematodes, 133;
of Acanthocephala, 177;
of Rotifers, 199, 213;
of Gastrotricha, 234;
of Kinorhyncha, 237;
of Polychaeta, 253;
of Polyzoa, 472 f.—see also Nephridium
_Exogone_, _308_;
attachment of eggs, 275;
reproduction, 278
Eyes, of _Leptoplana_, 8, 15;
of Polyclads, 26, 27;
development of, 30;
of larval Polystomatidae, 59, 60;
of Nemertinea, 102, 106;
of Nematodes, 128;
of _Gordius_, 166;
of Chaetognatha, 188;
of Rotifera, 215;
of Gastrotricha, 234;
of Kinorhyncha, 238;
of Polychaeta, 255, 272, 314, 337, 339;
of Oligochaeta, 354;
of Leeches, 393, 394, 395;
of Gephyrea, 417;
of Polyzoon larva, 509