VARIATION IN EPIDERMAL COLOR IN NAJADES. 255 



cussion of each species terminates with the evidence for association 

 of particular hues of the epidermis with the estimated age of the 

 animal and its sex. 



I. — Fusconaja flava 



SIMPSON RIDGEWAY 



Brown Brownish Olive. 



Greenish Brown Ecru Olive, Yellowish Citrine 



Brownish, Blackish, (when Bister, Dresden Brown, Sepia, 



old) Carob Brown, Seal Brown. 



Distribution of Colors as a Whole in Upper Ohio Drainage and 

 Iv. Erie. (275 shells). 



Dresden Brown 40% 



Bister :... 20% 



Brownish Olive. 20% 



Ecru Olive.:. 10% 



Sepia 10% 



Distribution of Colors as a Whole in Upper Ohio Drainage. 

 (225 shells). 



Dresden Brown 40% 



Bister ....: 20% 



Brownish Olive 20% 



Sepia .....10% 



Ecru Olive :.. 10% 



Distribution of Colors as a Whole in Upper Ohio Tributaries, etc. 



AUe'ny Alle'nv Mon'g. Mon'g. Ohio Ohio 



Tribs. River Tribs. River River Tribs. 



Dresden Brown 25% .25% 20% 20% 20% 



Bister. 25%-.-25% 20% 50% 



Sepia 50%..... .25% - 20% 20%. 



Ecru Olive 20% 20% 20% 



Seal Brown 25%.. 



Yellowish Citrine ....40%..... 25% 



Brownish Olive ...20% 40% 20% 25% 



Distribution of Colors as a Whole in L. Erie (50 shells). 



Carob Brown... , 30% 



Yellowish Citrine. 20% 



Seal Brown. .• 20% 



Dresden Brown. , 20% 



Ecru Olive 10% 



Distribution in L. Erie,- — localities. 



La Plaisance Cedar Presque Maumee 

 Bay Point Isle Bay R. Drain 



Carob Brown 66% 



Yellowish Citrine ^-40% 25% 33% 



Seal Brown 25% 



