2 CATALOGUE OF PTEROPODA. 



Les Mollusques Pteropocles, Lamk. Hist. ed. 2, vii. 412. 

 Stomatopterophora, Grai/, Med. Repos. 1821, 235. 

 Aporobranchiata (Aporobranclies), Blainv. Man. Malac. 480, 1825. 

 Fam. Pteropodes, Desk, in Lamk. Hist. ed. 2, vii. 213. 

 Cephalopliora Pteropoda Hyalacea, Alton, Verz. Conch, 12. 

 Therozoa pteropoda, Eichw. Zool. Spec. i. 310. 



Forskal {Faun. Arab. 124) and Lamarck {Hist. ed. 2, vii. 415) 

 compared the upper and lower part of the shell of a Hyalcea to the 

 valves of the Brachiopodes, which they regard as united together ; 

 but this is a mere analogical resemblance in the single species, 

 and not a true resemblance resulting from any affinity, as is proved 

 by the form of the valves of the other genera of the order. The 

 shell of the Pteropoda, is a single valves, analogous to the larger 

 valves of the Gasteropodes, and to one (and not both) of the valves 

 of the Brachiopodes. 



Loven compares the fins on the side of the head to the fins on 

 the side of the head of the foetal or first-hatched shell of Gasteropodes, 

 which are sometimes retained in the form of a fringe on each side 

 of the body in the adult animal, as Turbo, Trochus, &c. 



M. D'Orbigny gives the following as the result of his observ'a- 

 tions on the geographical distribution and habits of these animals. 

 Of the 29 species which he has observed, 14 are equally common 

 to all the seas, at least to the Atlantic and Pacific Ocean ; 11 have 

 only been observed in the Atlantic, and 4 in the Pacific : 17 of the 

 29 species are entirely nocturnal and 11 crepuscular. {Voy. Amer. 

 Merid. Moll. 72). 



The following genera or species have been erroneously referred 

 to this class : — 



1. Callianaria (diploptera), Peron Sr Lesueur, Ann. Mus. 1810, t. 



2, f. 16, " is probably a Beroe," Blainv. 



2. CiEROPTEEON, Sars, BesTc. 77, 1835; /sis, 1837, 757. Accord- 



ing to AUmann, Rep. Brit. Assoc. 1843 (see Athenteum, 1843, 

 852), this is the larva oi Buccinum undatum. 



3. Bellerophina (minuta), Forbes, Rep. Brit. Assoc. 1843, 132, is 



the shell of the larva of various genera of Gasteropodes. 



4. Steira, Eschsch. Isis, 1825, and 



5. Atalanta, Peron, are Gasteropodes. 



5. Pyrgo, Defrance, placed with the Pteropoda by Cuvier {Regn. 

 Anim. ed. 2) and Blainville {Diet. Sci. Nat.), is a Foramini- 

 fer allied to Biloculina. 



