NATURAL HISTORY. 
65 
ROOM III.] 
Aspidura 
Ophiurella— 20 
^Anoura 
Orbitremites 
Class IV. 
Fam. 2. Euryalidce. 
Astrophyton--22, 23 
Euryale—24 
“^/Natalia—24 
^Laspalia—24 
SPH1RONOIDEA. 
Sphaeronites 
Hemicosmites 
Cryptocrinites 
Class V. 
Fam. 2. ApiocriniticUe. 
Apiocrinites 
Holopus, &c. 
Fam. 3. 
CyathocrinitidcB. 
Cyathocrinites 
Marsupites 
Class III. Crinoidea. Fam. 4. Asterocomidce . 
Blasteroida. Fam. l^Pentacrinitidce,/X^tevocom^. 
Fam. 1. Pentremitidce. Comatula—24 [Continued at p. 74.] 
Pentremites — 24 Pentacrinites, &c. 
THE THIRD ROOM 
Contains the continuation of the collection of Ra¬ 
diated Animals, consisting of such as are covered with 
a smooth skin ; in some the outer skin is hardened into a 
sheath for the protection of the contractile body of the 
animal, while in others the body of the animal itself, as 
it enlarges in size, is gradually transformed into a hard 
and stony coral, by the continual deposition of earthy 
particles into the older part of its substance. 
This division (Leiodermata) contains three classes; 
the Acalepha or Sea Nettles, the Zoophytes , and the 
Polyzoa. 
The Acalepha, or Blubber-fishes , are so called from 
their being almost entirely formed of a soft, very cellular, 
jelly-like substance, which rapidly decomposes after 
death, without leaving any hard part or skeleton that can 
be preserved in a dry state ; they are destitute of any 
true stomach, but only have vesicles in their substance. 
They float free on the ocean. A few animals, which ap¬ 
pear to be intermediatebetween them and the Sea Anemo- 
nies, as the Porpita and Velella, have a cartilaginous plate 
sunk in their back, which keeps them of a defined form. 
The plate of the Porpita (Case 1) is circular and sim¬ 
ple, while that of the Velella (Case 1) is oblong, with 
an erect crest placed obliquely across its back. 
Cases 1 to 30, are occupied with the hard parts of 
Zoophytes, (Zoophyta,) which are so called because these 
animals are often crowded together in societies or families, 
in such a manner as to assume the form of trees. This 
form is taken to allow each of the individuals of which 
