208 HIPPOPODIUS HIPPOPUS. 



H. luieus and H. gleba, and the H. (Polyphyes) ungulata of Haeckel. The 

 H. neapolitanus of KoUiker and Weismann, was retained as distinct by Haeckel 

 ('88b) on the grounds that in it cf and 9 gonophores are associated with each 

 other, whereas in luteus they are all separate. The structure and arrange- 

 ment of the gonophores in this genus has been examined in detail by Richter 

 ( : 07) . He has shown that normally male and female gonophores are associated 

 together, but not with the numerical regularity ascribed to them by Weismann 

 ('83). I may add that all the specimens studied, both Atlantic and Pacific, 

 which were well enough preserved to show the gonophores at all, agreed with 

 his account. I therefore follow Chun ('97), Schneider ('98), and Lens and Van 

 Riemsdijk (:08) in uniting neapolitanus and luteus under H. hippopus Forskal. 



The status of the Polyphyes ungulata of Haeckel which is undoubtedly a 

 Hippopodius, is doubtful. It is retained by Chun as distinct, but united with 

 H. hippopus by Schneider. Leaving out of account the question of unisexual 

 or bisexual cormidia, ungulata is supposed to differ from hippopus only in the 

 presence of six prominent irregular teeth, four dorsal and two ventral, on the 

 margin of its nectophores. According to Schneider the presence or absence of 

 these teeth is merely an evidence of individual variation. And several of the 

 many nectophores of H. hippopus which I have examined approach Haeckel's 

 figures in this respect. It is of course the constancy of the difference which 

 must determine its importance in classification. Under the circumstances it 

 seems best to class H. ungulatus as a doubtful synonym of hippopus. 



I believe that Schneider was justified in substituting Forskal's name hippo- 

 pus for luteus as the specific designation of the one well-known member of the 

 genus, because, though Forskal's figures are not sufficiently detailed for absolute 

 determination, the probability of their identity with H. luteus is very strong. 

 That they do belong to some Hippopodius has generally been accepted; indeed 

 Chun, who uses the name luteus, includes hippopus as a doubtful synonym of it; 

 and since they can hardly be identified with H. ungulatus for the want of promi- 

 nent teeth, there seems no course open but to refer them to the only other species 

 of the genus. On general principles it is always desirable, for the sake of sta- 

 bility, to identify the older figures and accounts with actual species; and it 

 seems entirely justifiable in the present instance. 



Hippopodius hippopus (Forskal) Schneider. 



Gleba hippopus ForskAl, 1775, p. 14, 1776, taf. 43, fig. E; F'ewkes, '82b, p. 304, pi. 1, figs. 31-33. 



Gleba excim Otto, "23, p. 309, taf. 42, fig. 3 a-d. 



Hippopodius luteus QuoY and G.\imard, '27, p. 172, pi. 4A, fig. 1-12; Eschscholtz, '29, p. 146; Delle 



