130 THE NAUTILUS. 



The slinpe, indeed, is almost exactly tliat of the west Cuban M. 

 dejiticulatus — a species le?s closely striated and having a rimate base 

 and built-lorward cokimellar margin. M. petiliunus has narrower, 

 more separated striae and no denticulation below the suture ; more- 

 over, it has a shortly rimate base and fbrwardly-built columellar 

 margin. 



M. percom'cus (which I described as a variety of petitianus') is 

 doubtless a species distinct from petitianus, differing in sculpture 

 and the columella, which is not in the least built forward. It is 

 more strictly conic than trinidadensis, without sutural denticles, 

 otherwise the same. M. palenguensis, which I have not seen, seems 

 to be broader with a larger aperture. 



The specimens recorded as M. turricula Pfr. from Trinidad were 

 probably trinidadensis. I have not seen the form reported from 

 Cabo Cruz. 



Macroceramus canimarensis (Pfr.). 



A single specimen, typical in form and sculpture but white with 

 a corneous base, I found among rocks in a precipitous, shaded place 

 on the northwest side of La Vigia. It has already been reported 

 from Trinidad. 



Maci50Ceramus canimarensis rotundibasis, n. subsp. 



The shell differs from canimarensis by having only a very weak 

 trace of the subperipheral keel (which is strongly developed in cani- 

 marensis^; the base being much more convex than in canimarensis, 

 and not so strongly striated. 



" San Jose rocks " near Sancti Spiritus. 



I did not find this species living, but dug it from a bed of clay 

 formed by disintegration of the limestone. 



A LIST OF UOLLXTSCA FBOU THE MUSSELSHELL VALLET, MONTANA. 



BY S. STILLMAN BERRY. 



Except for the brief lists by Squyer (Nautilus, Vol. VIII, pp. 

 63-65, 1894) and Elrod (Bull. Univ. Montana, No. 10, pp. 170-174, 

 1902), there are very few molluscan records extant for the entire 



