CEPHALOPODA FllOM THE HOKKAIDO. 29 



Breadth of the last whorh 1.90 cm. 44. 



Width of umbiUcus. 1.40 „ 32. 



Shell broader than in other varieties ; whorls broaden slowly 

 toward the mouth, broader than high. Umbilicus wide, surrounded 

 by a vertical wall. Surface with striœ of the same type as in 

 the preceding variety but considerably coarser and more prominent. 



Localities : — On the Opiraushibets, about 35 miles from its 

 mouth, Prov. Teshio ; Makka-ushipe, a branch of the Sanushibe, 

 Prov. Iburi ; the Kikumezawa, a tributary of the Ikushumbets 

 Prov. Ishikari. Only one specimen from each locality was ex- 

 amined. 



Horizon : — Upper Ammonite -beds. 



SUBGROUP OF GAUDRYCERAS 

 CRASSICOSTATUM. 



GAUDRYCERAS CRASSICOSTATUM Jimbö sp. 



PI. IV., fig. 4. 



1894. Lytoceras crassicostatum Jimbö : 1. c. p. 36, PL VI. 

 figs. 7, 7 a. 



This species is exceedingly rare. It was first founded on a 

 somewhat water- worn but yet full grown specimen from Cape 

 Soya in the Province of Kitami. The writer has drawn up the 

 following diagnosis from an examination of a specimen which 

 belongs to a young stage. 



