THE NAUTILUS. 



11 



is not so inflated 27% against 32%. My measurements of 

 costata check readily with those of Simpson. 



Type no. 61.4720, card catalogue, Carnegie Museum. 



FuscoNAiA FLAVA var. PARVULA, uew variety. 



Variety parvula differs chiefly in size from fiava, being 

 smaller although proportionately higher and more inflated. 

 Epidermis of f,ava yellowish to dark horn-color ; in var. par- 

 vula, yellowish green, greenish olive. Surface with even 

 growth lines. Nacre of typical flava mostly white, tinged 

 with salmon in the beak; of parvula, pinkish-color or to pale 

 blue. 



Dimensions : 



f,ava 



Length Height Diameter 

 91 mm. 60 mm. 37 mm. 

 36 mm. 43 mm. 25 mm. 

 27 mm . 24 mm. 25 mm. 



var. parvula 

 Length Height Diameter 

 59 mm. 45 mm. 30 mm. 

 36 mm. 28 mm. 18 mm. 

 13 mm. 11 mm. 8 mm. 



Ratio of length to height and diameter in flava — 77% and 

 427o. 



Ratio of length to height and diameter in var. parvula — 

 79% and 51%. 



Similar results are obtained from Simpson's measurements 

 of flava. 



Type no. 61.4513 card catalogue, Carnegie Museum. 



The type specimens of the above three new varieties were 

 collected by Dr. A. E. Ortmann at Big Bend, Presque Isle 

 Bay, Lake Erie, July 8-12, 1910, and kindly entrusted to me 

 for description. They appear to be generally distributed 

 throughout Lake Erie. 



1. Walker, Bryant. "Unione Fauna of the Great Lakes." 



Nautilus, 27, 1913. 



2. Frierson, L. S. "Remarks on Classification of UnionidsB." 



Nautilus, 28, 1914. 



