CEPHALOPODA FPtOM THE HOKKATDo. 47 



Besides tlu'so sjx'ciincns, tlici'c are also a soiiicwliat. modified 

 form distinguished l)y a slightly wider iimbilieus and compressed 

 whorls. For the present, this is considered only as a variety. 



Localities : — The Yubarigawa ; the Ikiishnmbets and its 

 branches, the Yoshiashizawa and the Kikumezawa ; between the 

 Motomari and the Chietomanai, Söyagöri, Prov. Kitanii ; Shiintsuru- 

 hara, on the left l)ank of the Teshiogawa ; the Opiraushibets and its 

 tributaries, the Penke-kenebets and the Panke-kenebets, in the 

 Province of Teshio. The figured specimen was found in a pebble 

 from the Yübarigawa. 



Horizon : — Upper Ammonite-beds; abundant in the SWtphites- 

 beds. 



TETR AGONITES CRASSUS JiMRr. sp. 



189o. Lytoceras crassum, Jimp.ô : 1. c. p. oö (181), PI. YI. 

 (XXIT.), fig. 5 a, b. 



AVhorls nearly round, slightly flattened on the sides and 

 inflated ventrally, l)roader than high. Umliilicus moderate in 

 size, deep, surrounded by a perpendieukr wall. Involution about 

 il. 8urfece unknown, the only specimen being a cast of an 

 interior. The suture line is shown in Jimbö's work. The siphonal 

 saddle, however, is high and trigonal, and not so low or flat at 

 the apex as is shown in his figure. The external as well as the 

 first lateral lobe is asymmetrically bipartite ; besides, there are 

 four auxiliary saddles and corresponding lobes ; the first auxiliary 

 saddle is just at the umbilical edge whence the others incline 

 obliquelly downward to the nmlulical suture. 



JiMBo took the shape of the whorl to be the character 

 distingiushing the present speci(\s fi-om the precerliüg. He do- 



