34 



ART. 2. — H. YABE I CRETACEOUS 



the suture lines in detail up to the end of the outer volution. 

 In the writer's collection, there are also two specimens, referable 

 to the same species ; one of them is somewhat larger and flattend 

 on the sides by pressure, l)ut agrees in point of essential characters 

 with the above examples. 



The dimensions of these three examples measured are as 

 follows : — 



Ratio. 

 100 



42 



21 



Diaiueter. 



Height of tlie last whorl. 



Breadth of the last wliorl. 



Width of umbilicus. 



Involution. 



1). A specimen from the Kikumezawa. 



2). „ „ „ „ Urakawa; (pi. V., fig. 5.) 



3). ,, ,, „ ,, Urakawa. 



As is seen from the above table, the variation is very slight 

 in the three specimens except in size. 



This species is readily distinguished from H. Gardeni Baily,^^ 

 H. rembda Forbes'-' and H. Fayoli Grossouvre''^ by its narrower 

 umbilicus and higher whorl. It is, no doubt, much like H. 

 Welschl Grossouvre,^' with which at first glance it seems to 

 agree in nearly all its characters. But a closer examination 

 reveals a marked difference in the form of the whorl. In the 

 Japanese species the lateral sides converge gradually upward 

 to the ventral keel, while in the Grossouvre's figure of H. 

 Welschi, the sides converge very slowly to the ventral margin 

 whence they suddenly bend to the base of the keel. 



1) See p. 32. 



2) 1.0. 



3) I.e. 



4) I.e. 



