84 



easily understand the mistake of most zoologists (before Boas and Pklseneer) who considered 

 these animals as testaceous, and therefore classed them among the Thecosomata. 



As to the characters of the famil\-, I may refer to Boas ') and Pelseneer ^). Some 

 inaccuracies of Boas, who mistook the buccal apjjendages as most authors did before 

 him, were rectified b\' 1'elsexeer. I must, however, protest against one statement of both 

 authors, viz. that the posterior lobe of the foot is separated from the fins, as in all 

 Gymnosomata. I have examined a large number of specimens, but I always found this posterior 

 lobe connected with the fins (PI. \'I, fig. 153,//)- In this respect I agree with Huxley') 

 and Souleyet^). 



HalOpSyche Hronn. 



1825. Psyche Rang, Description d'un nouveau genre de la classe des Pteropodes, Ann. d. 



Sc. Nat., ser. i, vol. V, p. 284. 

 1827. Eurilna Rang, Description de deux genres nouveaux, appartenant a la classe des 



Pteropodes, Ann. d. .Sc. Nat., ser. i, vol. XII, p. 328. 

 1832. ? Cynnbitlia (part.) Quoy et Gaimard, Voyage de 1' Astrolabe, p. 376. 

 1856. Eurybia Woodward, A Manual of the Mollusca, p. 206. 



1S62. Halopsyche Bronn, Die Klassen und Ordnungen des Thierreichs, Bd. Ill, p. 645. 

 1862. Thcceurybia Bronn, Ibid., p. 645. 



From the description and figures of OuoY and Gaimard who described a "■Cyiiidzilia 

 ii07'folkensis\ it is impossible to decide to which form these indications must be applied. Most 

 probably a species belonging to the genus in question is meant. 



At present only one species is sufficiently well known, which has been collected in 

 considerable quantities by the Siboga Expedition. As to the forms Psyche globtilosa and 

 Euribia Iicviispherica^ both described by R.\ng, we know too little about them as to express 

 any opinion regarding their systematic jjosition, but it would be very interesting to obtain 

 further information, as the fins in these animals attain excessive development. 



I. Halopsyche gazidichaudi (Souleyet). (PI. VI, figs. 153 — 156). 



1852. Euribia gaudichaudii Soulej-et, Voyage de la Bonite, vol. II, p. 253, pi. XIV', figs, i — 6. 

 1859. Kiti'ybia gaudicliaiidi Rlacdonald, On the anatomy of Eurybia gaudicliaiidi, Transac. 



Linn. Soc. Lond., vol. XXII, p. 245, pi. XLIII. 

 1883. Thcceurybia norfolkensis Ray Lankester, Mollusca, Encyclop. Brit., 9"' Ed., vol. XVI, 



p. 666, fig. 83. 



1886. Halopsyche gaudicJiaudii Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi etc., 



K. Dan.sk. Vidensk. Selsk. Skrift., 6 Raekke, Bd. IV, p. 173, pi. VIII, fig. 119. 



1887. Halopsyche gaudicliaiidi Pelseneer, Chall. Rep. LVIII, p. 55, pi. Ill, figs. 7 — 9. 



Living animals: 



Stat. 141. 1° o'.4 S., i27°25'.3E. 28 spec. 



Stat. 143. 1° 4.5 S., i27°52'.6E. 3 spec. 



1) Spolia athuitica, p. 171 — 173. 



2) Chall. Rep., LVIII, p. 52—53. 



3) On tlic .Morphology of the cephalous Mollusca, Philos. Transact. (1853), pi. IV, fig. 3. 



4) Voyage de la lionitc, vol. II, pi. XV, fig. i. 



