623 
Figs. 23 and 24. Yrocholites canadensis, Hyatt; Loc., Falls of Montmo- 
rency (?); Coll. Mus. Comp. Zoélogy, Bronn Coll. 
Fig. 23. Much enlarged. ‘The siphuncle shows through the transparent venter 
of the nepionic volution and it passes from subdorsan in the paranepionic below 
to centren in the metanepionic above. The umbilical perforation appears beyond 
the siphuncle and has a well-developed dorsal furrow, can also be seen; Fig. 24 
shows the gibbous outgrowth of the dorsum in the umbilical perforation at some 
distance from the gyroceran bend. 
Fig. 25. Zrocholites (Lituites) internastriata (sp. Whitfield), Hyatt. This 
was drawn from the centre of his original specimen, Bwl/. Am. Mus. Nat. Hist. 
LV. Y., Pl. xxix, Fig. 6, enlarged to show the centren position of the siphuncle in 
the first septum and its gradual approach to the dorsum in the paranepionic whorl 
as in 7: canadensis. This also shows a much larger umbilical perforation than 
is found in Canadensis or ammonzus or the species figured by Holm. 
Fig. 26. Zrocholites sp.? after Holm, 7al. Abh. Dames et Kayser, iii, Pl. v, 
Fig. 11, to show the probable beginning of the siphuncle to be nearer the centre 
than is described by him. His Fig. 9 of Zrocholites incongruus shows also a 
small umbilical perforation and the siphuncle subdorsan, but its tip or caecum is 
directed towards the centre of the apical chamber. 
