[Sidenote: SYSTEM OF LAMARCK.]
"Lucy and I have been collecting a variety of species," said Charles
to his father, "since our last lesson in conchology. We have also
seen several large collections of shells, one of which was arranged
according to Lamarck. I was much pleased with the new genera taken from
_Buccinum_, _Bulla_, _Turbo_, and others.
"We are desirous of gaining information on this new system, if you can
spare a little time to attend to us."
"Willingly," replied Mr. Elliot; "I anticipated such a request, and
have been making lists of the genera belonging to each system; so that,
upon meeting with a new genus, you may be able to ascertain with some
accuracy its place in the old arrangement.
"Lamarck founds his system upon the structure and form of the animals,
so far as they have been ascertained, and with which the exterior, or
shell, must necessarily coincide. The conchology occupies the three
last _classes_, and _one order_ of another class, in the well-known
work which I have before mentioned to you.
[Sidenote: ANNULARIA. SEDENTARIA.]
"To begin with the 3rd Order of the 9th Class:--
Class, _Annularia_. Order, _Sedentaria_, Annulated Worms.
Lamarck. Linnæus.
_Siliquaria_, taken from _Serpula_.
_Dentalium_, ---- _Dentalium_.
_Pectinaria_, ---- _Sabella_.
_Sabellaria_, ---- _Sabella_.
_Spirorbis_, }
_Serpula_, } ---- _Serpula_.
_Vermilia_, }
_Galeolaria._
_Magilus._
"There has been much variation in the opinions of naturalists
respecting the proper place of genus _Dentalium_. Cuvier, a very
celebrated writer, agreed nearly with Lamarck; but still more recently
it has been considered as nearest to a new genus, _Fissurella_,
(_Patella_.) The fossil-shells are found in London clay in great
numbers; in the marle at Folkstone, &c.
"_Spirorbis._ All the species are minute, fixed upon sea-weeds, and
other marine substances. The animal which inhabits them is of a deep
red colour.
"_Galeolaria_ is a New Holland genus.
"_Magillus_ is found in the Isle of France; the shell is sometimes
three feet in length.
* * * * *
[Sidenote: CIRRHIPEDA--FIRST ORDER.]
"Class 10th. _Cirrhipeda_, contains two orders: the first, _sessile_,
or placed upon some other body; the second, _pedunculate_, and fixed at
the extremity of the pedicle to other substances.
"The class takes its name from the _Cirrhi_, or feathery tentacula. The
genus _Lepas_ only is contained in the _Cirrhipeda_ class.
* * * * *
"1st Order. Shells Sessile.
Genera.
_Tubicinella._ }
_Coronula._ }
_Balanus._ }
_Acasta._ } All included in _Lepas_.
_Creusia._ }
_Pyrgoma._ }
"The first genus contains but one species; the shell is buried up to
its aperture in the skin and fat of whales.
"The second, _Coronula_, is found inserting itself in the sea-turtle,
&c.
"_Balanus_ is known to you as the acorn-shell; a genus widely diffused;
abounding on rocks, shells, and wood, in large colonies.
[Sidenote: CIRRHIPEDA--SECOND ORDER.]
"_Acasta_ is found upon sponge.
"For examples of _Creusia_, we must examine our _madrepores_, and other
corals; the shells of this genus are either affixed or buried in them.
"_Pyrgoma_ likewise adheres, or penetrates into corals.
"In the 'Penny Cyclopædia,' under the word _Cirrhipeda_, you will find
much useful information, and some plates that will give you a good idea
of this class. In the British Museum you may see many of the species,
and may thus make yourselves familiar with them.
* * * * *
"2nd Order. Shells pedunculated.
_Pentalasmis_, (_Anatifera_.) }
_Pollicipes_. } _Lepas._
_Cineras._ }
_Otion_, ear-barnacle. }
"We have already noticed _Pentalasmis_, or barnacle, (Plate
2.) The generic name is changed by later writers; so are those of
the two last.
"_Pollicipes_ resembles _Pentalasmis_, with a shorter pedicle, which
is rough. The natives of Goree are said to eat a large species of
_Pentalasmis_."
"I think we shall not fail to recollect the _Cirrhipeda_ class," said
Lucy; "the forms of the shells are remarkable: and those that live on
_Madrepores_ I shall search for immediately; but what a number of new
genera are taken from the single one of _Lepas_!"
[Sidenote: EXPLANATIONS.]
"Since the time of Linnæus," replied Mr. Elliot, "many more
observations have been made upon the shells that he had examined;
many new shells, both genera and species, have been found; and there
is little doubt that, if Linnæus had now been living, he would have
found his own genera inadequate, and would have established new ones.
I fear you will have to regret the opposite extreme, and complain of
the multiplicity of new genera, and new names. Our object is to become
familiar with the shells, and by knowing the Linnæan name, and that
bestowed by Lamarck, two authorities very generally cited, you may
understand what species is alluded to by modern conchologists. The
names of Bruguieres, Leach, Gray, and Sowerby will often occur among
many others.
"For example: let us take the plate of a remarkable multivalve; you
find that it is named _Scapellum vulgare_, and that it is so called
by Leach. Below, you find '_Pollicipes scapellum_, Lamarck;' and
on referring to our comparative lists we find that the shell was a
_Lepas_, (_L. scapellum_ of Linnæus.)"
[Sidenote: EXPLANATIONS.]
"But they have kept the specific name," observed Charles.
"And made it the generic," said Mr. Elliot; the peculiarities and
variations are deemed insufficient to found a new genus.
"Here we shall pause for the present; and then proceed to the 11th
Class."