CEPHALOPODA FROM THE HOKKAIDO. 21 



lateral sides. All of these striœ are very fine, but their size 

 varies much in each individual. The periodic ribs are round and 

 parallel to the stride, five of them being on each volution, and 

 correspond to faint grooves on the cast of the interior. These 

 ribs are also covered with fine striœ. 



The suture line has one external, two lateral and three aux- 

 iliary saddles, diminishing gradually in size toward the umbilical 

 suture. 



The above description and that of Yokoyama clearly indicate 

 that this Ammonite is closely related to G. muUiplexiim Koss.^^ 

 { = G. Sacya Forbes var. multiplexum Stoliczka), with which 

 Yokoyama indeed identified it, while Kossmat considered it to 

 be G. Sacya. The former species is distinguished from this by 

 the difiereut forms of the auxiliary saddles. The latter, when 

 compared with this, possesses less numerous volutions, although 

 it is often impossible to find this distinction, when we have not 

 full grown forms before us. G. dcnmanense AVhiteaves'-^ sp. 

 f]"om tlie Vancouver Cretaceous which is identified with G. Kayei 

 Forbes by Kossmat, is also hardly distinguishable from the 

 young forms of the present species. 



Whiteaves, after a direct comparison of the sj)ecimens of 

 his G. denmaneiise with those of G. tenuiliraium which had been 

 sent to him for examination, informed the writer that he saw 

 at pi-esent, no reason why the latter should be distinguished from 

 the former. G. alamedense J. P. Smith''^ is also certainly related 

 to G. tenuiUratani, but according to the above author to whom 



1) Kossmat: 1. c. p. 25 (121), PI. I (XV), figs. G a, b, c. 



2) Whiteaves: On Some Fossils from the Nanaimo group of the Vancouver Cretaceous 

 1895. P. 129, PI. n. figs. 1-2. 



3) Smith : Tiie Development of Lyloccra^ and riijlloccras. Proc. Calif. Acad. Sei. Series. 

 lU. Vol. 1. Ko. 4. 1S98. P. 130. 



