the Genera and Species of Starfish. 77 
3. Asterina: Linck only knew one species which he put at the end 
of his Pentaceros. 
4. Anseropoda = Palmipes, Linck. 
5. Linckia = Pentadactylosaster, Linck. 
M. Agassiz, in the Memoirs of the Neufchatel Society, published a 
new arrangement of the Echinodermata, which has been abridged into 
the Annales des Sciences Naturelles, and from thence translated into 
the Annals of Natural History, i. 440, in which he has changed the 
names of some of Nardo’s genera, and added some others for extra- 
European and fossil species, as follows :— 
Asterias = Astropecten, Linck.=Stellaria, Nardo. 
Ceelaster, fossil. 
Goniaster = Pentagonaster and Pentaceros, Linck. 
Ophidiaster, a new species. 
Linckia = Cribella = Pentadactylosaster, Linck. 
Stellonia, Nardo = Stella coriacea, Linck, &c., as above. 
Asterina, Nardo. 
Palmipes, Linck. = Anseropoda, Nardo. 
. Culcita, Agassiz, for Ast. decides, Lam. 
M. Agassiz generally quotes for the type of his eet yc genera 
the same species as those cited by Nardo. 
Class HYPOSTOMA, Gray, Syn. Brit. Mus. 
Having a bag-like stomach, with a single opening serving as 
mouth and vent. ‘The ovarial pores are placed round the mouth. 
The body is inclosed in a hard skin and supported by variously 
shaped calcareous pieces. 
It should be remarked, that the hard parts of these animals, whe- 
ther they are in the form of ¢essere, as in the Echinida, or of ossi- 
cula, as in the Hypostomata, or in that of spines, as in either, are 
evidently the hardening of certain parts of the cellular substance 
or skin, and these hard parts retain-their organization and vitality 
during the life of the animal ; consequently they are not inorganic 
secretions, like the shells of mollusca, as they have generally been 
considered, but have far more relation to bones and coral, and like 
them form a peculiar kind of body intermediate between shells and 
the skeletons of vertebrata. ‘‘ These pieces,” as I have observed in 
the Synopsis of the British Museum, “are formed by the earthy par- 
ticles being deposited round certain definite spots in the skin, and 
as they are developed they assume a definite arrangement into cer- 
tain distinct shapes peculiar to the different kinds: although these 
are strongly united together by the skin, and have a kind of organiza- 
tion during the life of the animal, they may easily be separated from 
each other after death, and then appear like separate bones. ‘This 
structure allows the animal to increase both the size and the num- 
ber of the pieces that compose its protecting case as the body grows, 
and also to repair, by the deposition of fresh calcareous particles on 
the skin of the healed part, any injury which the animal may have 
received from external accidents during its life.” 
This structure is not so easily demonstrated in the internal bones 
Ann. & Mag. Nat. Hist. Nov. 1840. N 
OD ST RO 1D 
