DESCRIPTION OF GENERA AND SPECIES. 



PTEROPODA, Cuvier. 



GYMNOSOMATA, de Blainville. 



Deutocephcda, Wagner, 1885. * 

 Pterota, Boas, 1886. 2 



THE GENERA AND FAMILIES OF GYMNOSOMATA. 



Many genera of Gymnosoniatous Pteropods have been described, but several of them 

 cannot be retained. 



I. Because they are synonyms : — ■ 



1. jEgle, Oken, 3 = Pneumonoderma, Cuvier. 



2. Cirrifer, Pfeffer, 4 = Pneumonoderma, Cuvier. 



3. Cliodita, Quoy and Gaimard, 5 = Clione, Pallas. 



4. Euribia, Rang, 6 non Hiibner = Halopsijche, Bronn. 



5. Pneumodermo'psis, Bronn, 7 = Dexiobranclisea, Boas. 



II. Because they only represent the larval state of genera of which the adult is 

 already known : — 



1. Trichocyclus, Eschscholtz, 8 in which the larvae of different genera have been 



placed. 9 



2. Trizonius, Busch, 10 = larva of Pneumonoderma. 



1 Die Wirbellosen des weissen Meeres, Bel. i. p. 119. 2 Spolia Atlantica, p. 179. 



3 Lehrbuch der Zoologie, Bd. i. p. 326. 



4 Uebersicht der auf S. M. Sehiff " Gazelle " und von Dr. Jagor gesammelt Pteropoden, Monatsber. d. k. preuss. 

 Akad. d. TViss. Berlin, p. 249, 1879. 



6 Description de cinq genres de Mollusques, Ann. d. Sci. Nat., ser. 1, t. vi. p. 74, 1825. 



6 Description de deux genres nouveaux appartenant a la classe des Pteropodes, Ann. d. Sci. Nat., ser. 1, t. xii. 

 p. 320, 1827. ' Die Klassen und Ordnungen des Thierreichs, Bd. iii. pp. 584, 645. 



8 Bericht iiber die zoologische Ausbeute wahrend der Reise von Cronstadt bis St. Peter und Paul, Oken, Isis, 1825. 

 p. 735. 



9 Trichocyclus dumerili, Esch. = larva of Spongidbramchsea australis, d'Orb. Trichocyclus mediterranem, Costa = larva 

 of Clionojjsis krohni, Troschel. 



10 Beobachtungen iiber Anatomie und Entwicklung einiger wirbellosen Seethiere, p. 112. 



(ZOOL. CHALL. EXP. PART. LVIII. 1887.) Mmni 2 



