THE NAUTILUS. V5 



teeth is heavy and bears one or more tubercles ; lateral teeth as 

 in radiata; anterior adductor muscle scar, posterior adductor 

 muscle scar, and dorsal muscle scars more heavily impressed 

 than in radiata ; nacre bluish-white, slightly iridescent. 

 All of the specimens seen have their umbones eroded. 

 Length 56, height 36, breadth 21 mm. $. 

 " 53, 35, " 20 mm. 9. 



" 51, 37, " 20 mm. $. 



60, 40, 24 mm. ?. 



66, 41, " 27 mm. <?. 



63, 41, 27 mm. 9. 



Types in collection of the New York State College of Forestry 

 at Syracuse University ; cotypes in collection of the Academy 

 of Natural Sciences of Philadelphia and Dr. Bryant Walker, 

 Detroit, Mich. 



This race of Lampsilis is related to both radiata and luteola. 

 From the latter it differs in the more elliptical sometimes orbi- 

 cular outline of the male shell, the olive green and brown epi- 

 dermis and in the cardinal teeth which are heavier and broader, 

 not so deeply serrated, and of different shape. From radiata it 

 differs in its outline, in its epidermis, which is not as rough, 

 and in the cardinal teeth, which are not as heavy, and are 

 more elevated, triangular and pyramidal. The pits at the base 

 of the cardinal teeth are deeper. 



This race is common in Oneida Lake and is very uniform in 

 the characteristics noted. It was previously listed 1 as Lampsilis 

 borealis but specimens of borealis* from the type locality, Duck 

 Island, Ottawa River, Ontario, Canada, received from Dr. 

 Walker, show that it is not that species, true borealis having a 

 heavier, more inflated shell, heavier and differently shaped 

 cardinal teeth and an epidermis like that of radiata. Small 

 females of oneidensis have a superficial resemblance to Lampsilis 



1 The Fresh-water Mollusca of Oneida Lake, New York. NAUTILUS, xxx, 

 page 7, 1916 ; The Relation of Mollusks to Fish in Oneida Lake. Tech. Bull. 

 No. 4, New York State College of Forestry at Syracuse University, page 257, 

 fig. 44, 1916. The references to borealis in the latter publication should be 

 changed to oneidensis. 



'Trans. Ottawa Field Nat. Club, No. 3, page 53, 1882. 



