232 THE AMERICAN MIDLAND NATURALIST 



Erie. White, in any abundance, is found most in the Upper Ohio 

 Drainage. 



In the Upper Ohio Drainage: 



Pinkish colors predominate in the Allegheny Tributaries, white 

 pearl blue in the river. The Ohio and Tuscarawas Rivers show the 

 greatest percentage of Pearl Blue. A fading out is seen descending 

 the Allegheny. Characteristic stream colors are, 



Light Pinkish Lilac in the Allegheny. White in the Ohio. 



In Lake Erie: 



Where Cedar Point possesses more pearl blue, Presque Isle has 

 more pinkish and purplish colors. 



In Chautauqua Lake the prevailing color is a vinaceous pink. 



Observation on Sex Correlative Coloration, etc. (jj shells). 



The nacre of the males seems to be prevailingly purplish; that 

 of the females, pinkish. Pearl Blue is about evenly represented 

 in both sexes. 



1 1 . — Lampsilis luteola 



SIMPSON RIDGEWAY. 



Blue Pearl Blue 



Bluish White Pale Grayish Blue Violet, White 



Straw Colored, Pink Light Pinkish Lilac, Pale Rhodonite Pink. 



Distribution of Colors as a Whole in the Upper Lhio Drainage and 

 Lake Erie (289 shells). 



Light Pinkish Lilac, etc.. 35 % 



Pearl Blue, etc.... 13% 



White, etc.... 17% 



Pale Grayish Blue Violet, etc 35% 



Distribution of Colors as a Whole in Upper Lhio Drainage 

 (187 shells). 



Light Pinkish Lilac, etc 30 % 



White, etc 14% 



Pearl Blue, etc 24% 



Pale Grayish Blue Violet, etc 35% 



DistributiA;n in Upper Lhio Tribs., etc. 



Alle'nv Alle'ny Monong. Monong Ohio Beaver 

 Tribs. River Tribs. River River Drainage 



Light Pinkish Lilac, etc 43% 40%......50% .60% 50% 42% 



Pale Grayish Blue Violet, etc 14% 30% 50% 3i% 



Pearl Blue, etc 16% 30% 15% 13% 



White, etc .-- .,.......,..,..27% , ..-.40% 35% 14% 



