228 ANOYLUS. 
vexly much elevated, apex obtuse, subcentral, 
texture delicate, surface rather smooth. 
Length 8, width 6, alt. 4 mill. 
Klamath River. 
This shell is larger, narrower, more ele- 
vated, and not so solid as Prof. Haldeman’s 
A. crassus, and it does not approach in outline 
to either of Mr. Lea’s new West Coast species, 
both of them being more narrowly elongate. 
It is one of our largest species. 
15. ANCYLUS SUBROTUNDATUS, Tryon. 
Plate 2, fig. 15, 16. 
Shell large, very fragile, oval, nearly round ; 
convex, but little elevated; apex obtuse, 
nearly central. 
Length 8, width 6:5, alt. 3 mill. 
Umpqua River, Oregon. 
(22) 
