10 ART. 2. H. Y A BE I CRETACEOUS 



separated from one another b}^ a tolerably broad and flat interval. 

 Kibs sharj), always simple and smooth, becoming somewhat feebler 

 and more flexuous on the umbilical side. 



The suture line has been only partly examined. It shows a 

 single lateral saddle and lobe, both of which are twice deeply 

 bifid and finely incised. The siphonal saddle is slightly higher 

 than the lateral one. 



One of the specimens (fig. 2.) is from the Sraphites-heds of the 

 Opiraushibets. It is nearly a volution of a sinistral shell, less 

 than 4 mm. in diameter at the smaller end, and about 8 mm. at 

 the other end. One half of this whorl is furnished with 45 ribs 

 of which 8 are broader and more elevated than the others, 

 especially on the outer side. The smaller ribs which are found 

 between these larger ones number 4 to 10. All the ribs are ai- 

 ranged transversely, except near the larger end of the whorl 

 ^vhere they are a little oblique. 



The second specimen is from the Yril)arigawa. It is a volu- 

 tion of a dextral shell, a little larger than the one mentioned 

 above. As in Heieroceras Otsukai,^^ the siphon bends downward 

 from the median line at a certain point of the external side of 

 the whorl. 



Another example drawn in fig. 3, pi. III., is a small frag- 

 ment of a larger, dextral shell. These figures show in suflficient 

 clearness the mode of arrangement of the ribs on the whorl. 



Localities : — The middle course of the Opiraushibets, and the 

 Yflbarigawa. Four specimens from the former locality and the 

 two from the latter have been examined. 



Horizon : — Scaphites-heds. 



\) Vide p. 1."). 



