NEOZOIC INVERTEBRATES 115 



Saxidomus popofianus sp. nov. 



Pl. X, fig. 4. 



Shell rather evenly ovate, inequilateral, with low beaks nearer the 

 anterior end; dorsal slopes slightly descending, the beaks near the 

 anterior third of the shell; ends evenly rounded, base moderately 

 arcuate ; internal margins smooth ; muscular scars deeply impressed ; 

 pallial line rather distant from the ventral edges of the valves, with a 

 small, short, ascending subangular sinus free from the pallial line 

 below ; external surface rather rudely and irregularly concentrically 

 sculptured. Length of internal cast 50, height 37, diameter 38.5 mm. 



Locality. Popof Island, 3372. 



This is one of the most abundant species of the Miocene beds of 

 Popof Island. 



? Callocardia (Pitaria) kincaidli sp. nov. 



Pl. X, fig. I. 



Shell elongate-ovate, plump, inequilateral, with large and promi- 

 nent beaks three-tenths of the length behind the anterior end ; anterior 

 dorsal slope short, excavated ; posterior slope longer and nearly 

 straight ; pointed rounded at both ends, base arcuate ; pallial line 

 with a short, wide, rounded, ascending, free sinus ; exterior concen- 

 trically striated. Length 50, height 35, diameter 21 mm. 



Locality. Popof Island, 3372. 



This species is referred to the above group on account of its gen- 

 eral aspect, as the hinge is inaccessible. It is quite common in the 

 beds referred to. It is named in honor of Mr. Trevor Kincaid, of 

 Seattle, who collected it with other fossils from Popof Island. 



Dosinia ? alaskana sp. nov. 



pi. x, fig. 7. 



Shell suborbicular, rather convex, with very high prominent beaks 

 nearer the anterior end ; anterior slope short, deeply excavated ; pos- 

 terior slope convexly arcuate ; base arcuate ; pallial sinus short, angu- 

 lar, free from the pallial line below ; internal margins simple. Length 

 55, height 53, diameter 22 mm. 



Locality. Popof Island, 3372. 



This species has the hinge obscured, but is probably a Dosinia. 

 The surface is concentrically sharply striated. 



