20 PALAEONTOLOGY OF CALIFORNIA. 



on the sides; separated from each other by about one-third the 

 width of the volution. Surface marked by fine lines, which arise 

 in the umbilicus ; curve slightly backwards and then forwards on 

 the side, and, as they pass over the angle between the side and 

 back, again curve backwards, making a deep sinus on the dor- 

 sum. 



/ 



This shell is allied in form to N. bidorsatus, Schlot. The sides are, in the pre 

 sent species, more strongly inclined towards each other; and the dorsum is con 

 vex, instead of being excavated. The umbilicus also is smaller. 



Locality : With the preceding species. 



1ST. MULTICAMERATUS, n. S. 

 PL 3, Figs. 4, 5. 



SHELL broad, subglobose; whorls deeply embracing; sides com 

 pressed and rapidly converging ; dorsum broadly grooved ; um 

 bilicus apparently quite small, partially obliterated in the speci 

 men. Septa numerous, crowded, arching forwards on the sides, 

 and curving slightly backwards on the back. Siphuncle unusually 

 large. Surface marked by revolving, somewhat irregular elevated 

 lines. 



Figure, natural size. 



Locality: A single specimen was found by Mr. R. Homfray at "Dun Glen," 

 near the Auld Lang Syne Mine, Sierra District, Humboldt County, Nevada Ter 

 ritory. 



