40 AET. 2. H. YABE : CRETACEOUS 



of the inner whorls. Aperture somewhat elongated, higher than 

 broad. Surface of the shell apparently quite smooth, with a 

 faint groove on a portion of the anterior whorl where the shell 

 has been taken off'. The groove curves strongly forward in 

 crossing the ventral surfece where it is more distinct than on 

 the lateral sides. Suture line with four saddles and four lobes 

 on each lateral side, and the two on the umbilical Avail. These 

 saddles and lobes diminish very gradually in size and are all 

 similar in shape, the former being bipartite and the latter tri- 

 partite excepting the three or four innermost ones which are 

 always simple. 



There is scarcely any doubt as to the existence of a close 

 relationship between this species on the one hand and Desmoceras 

 inane Stoliczka^' from the Utatur Group and 1). diphylloides 

 Forbes-^ from the Ariyalur and the Voludayur group of S. India 

 ou the other. D. diphylloides agrees fairly well with this species 

 in its general outline if we except the slightly narrower umbilicus 

 and more numerous saddles and lobes. D. inane is thicker than 

 the Japanese species although it much resembles it in the suture 

 line. Ammonites Sehvynknuis Whiteaves"" from the Horizon 

 A of Vancouver Island and 1). pyrenaicam CjROSSOUVRe'" from 

 the Santonien of France are also our distant allies. 



From 1). Bawsoni Whiteaves var., the present species is 

 distinguished by the higher whorls and nar]-ower umbilicus. But 

 as the specimens of these two species examined by the writer 

 are quite different in size, the above distinctions must be taken 



1) Stoliczka : I.e. p. 121, 111. LIX., iig. IS (non fig. 14).— Kossmat : I.e. p. 107, pi. 

 XIX., figs. 6-7. 



2) Stoliczka: I.e. p. Ill», \A. LIX., figs. S-9.— Kos.smat : I.e., p. I(i8, pi. XIX., figs. 8-9. 



3) Whiteavks: I.e. pt. 2, p. 104, pi. XII 1., fig. 1; pt. 5, p. .'îôl. 



4) Gkossouvre: Aniru. <le la Craie supérieure, p. 168, pi. XXXVII., figs. 9 a, b, c. 



