the Genera and Species of Starfish. 177 



3. Asterina : Linck only knew one species which he put at the end 

 of liis 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 : — 



1. Asterias = Astropecten, Zittc&. = Stellaria, Nardo. 



2. Ccelaster, fossil. 



3. Goniaster = Pentagonaster and Pentaceros, Linck. 



4. Ophidiaster, a new species. 



5. Linckia = Cribella = Pentadactylosaster, Linck. 



6. Stellonia, Nardo = Stella coriacea, Linck, &c, as above. 



7. Asterina, Nardo. 



8. Palmipes, Linck. = Anseropoda, Nardo. 



9. Culcita, Agassiz, for Ast. discoidea, Lam. 



M. Agassiz generally quotes for the type of his European 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 tessera, as in the Echinida, or of ossi- 

 cular 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 



