THE NAUTILUS. 77 



The radiata of Oneida Lake are not typical being more in- 

 flated, quadrate in outline rather than elliptical, the rays are 

 not as even or as numerous and the color of the shell is usually 

 yellowish rather than greenish, in this respect approaching 

 luteola. The radiata type in the lake shows a decided variance 

 toward the form of the shell herein described as oneidensis. 



The only safe criterion for separating the Oneida Lake radiata 

 from luteola is by the form of the cardinal teeth. INIany years 

 ago F. R. Latchford ^ tersely characterized these differences as 

 follows : " In C/. radiatus these are short, erect, and triangular. 

 In U. luteolus they are long, curved, compressed, and oblique." 

 The dull, rough epidermis is characteristic of radiata but, as 

 noted in Oneida Lake specimens this may not be present or 

 typically developed. It seems evident that in Oneida Lake 

 evolutionary forces have been at work upon this group of the 

 Naiades and that the form herein described as oneidensis is the 

 result. 



Figures 1 and 3 represent male, 2 and 4 female individuals. 



My thanks are due Dr. Bryant Walker for assistance in work- 

 ing out the relationships of this race and also Dr. C. C. Adams, 

 of the New York State College of Forestry, for the loan of the 

 plate upon which the race is figured. 

 New York State College of Forestry, 

 Syracuse University. 



DESCRIPTIONS OF NEW SPECIES FROM THE CRETACEOUS AND 



TERTIARY OF THE TESLA, PLEASANTON, SAN JOSE, AND 



MT. HAMILTON QUADRANGLES, CALIFORNIA. 



BY E. B. HALL AMD A. \V. AMBROSE. 



{Concluded from page 71) 

 Pholadomya harrigani, n. s. Hall and Ambrose. 



Description. Shell, right angle, thick; beaks low, anterior, 

 in-curved, nearly touching. Buccal end abruptly truncated at 



'Notes on the Ottawa Unionidae. Trans. Ottawa Field Xat. Club, No. 3, 

 page 51 , 1882. 



