66 
NATURAL HISTORY. 
[N. ZOOL. GAL. 
Aspidura 
Ophiurella—20 
Anoura 
Fam. 2. Euryalidce. 
Astrophyton—22, 23 
Euryale—24 
Natalia—24 
Laspalia—24 
Class III. 
BLA STEROID A. 
Fam. 1 . Pentremi tides. 
Pentremites—24 
Orbitremites 
Class IV. 
Sph.eron oid^a. 
Spbaaronites 
Hemicosmites 
Cryptocrinites 
Class V. i 
Crinoidea. 
Fam. \.Pentacr\niiides . 
Comatula—24 
Pentacrinites, &c. 
Fam. 2. Apiocrinitides . 
Apiocrinites 
Holopus, &c. 
Fam. 3. 
Cyathocrinitides . 
Cyathocrinites 
Marsupites 
Fam. 4. Aster ocomidee. 
Asterocoma. 
[Continued at p. 75.] 
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 an}' 
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 
