30 



Shell discoidal, compressed ; composed of about 7 volutions. 

 Umbilicus very wide, about twice as broad as the height of the 

 whorl, becoming gradually narrower as the shell grows. The 

 inner volutions slightly inflated, merely touching one another, 

 but the last volution is higher than broad, embracing one half 

 of the preceding one. The surface sculjDture is similar to that of 

 G. tenuillratuvis but the striœ become 2;raduallv finer toward the 

 mouth where the shell appears almost smooth. The whorls of 

 the later stages possess many thick periodic ribs as shown in fig. 

 7, PI. VI. in the work quoted above. 



This species, being characterized by the peculiar sculpture 

 of the adult specimen, and the very loosely coiled volutions of 

 the young individual, is easily distinguished from others. 



Locality : Cape Soya, Prov. Kitami. 



Horizon : Upper Ammonite-beds. 



GAUDRYCERAS DENSEPLICATUM Jimbö sp. 



1894. Lyiocerru denseplicatum JiiMBö : 1. c. p. 36 (182), PI. 

 III. fig. 1. 



This beautiful but rare form is represented by a single specimen 

 in the writer's collection, this and the type figured by Jimbö 

 being the only ones found up to the present time. The writer's 

 specimen is less complete than Jimbô's, having only a part of 



