VARIATION IN EPIDERMAL COLOR OF NAJADES. 26 1 



or old ^ge colors of brown and black may begin at 3-4 years and 

 be complete at 6. No one color or group of colors was found to be 

 peculiar of any age. 



Observation on Sex-Correlative Coloration as Related to Epidermal 



Color. (15 shells). 



Males have a larger proportion of clear brown colors, young 

 males are largely brownish olive. Females are represented by 

 larger proportions of reddish browns, young females being Buffy 

 OHve. 



4. — Pleuroherna ohliquum coccineum 



SIMPSON RIDGEWAY 



Tawney or yellowish green 



when young. Buffy Citrine 



Brownish Prouts Brown, Mummy Brown, Mars 



Brown, Aniline Black 

 Reddish Brown Seal Brown, Warm Blackish Brown. 



Distribution of Colors as a Whole in Upper Ohio Drainage and 

 L. Erie (263 shells.) 



Prouts Brown ...30% 



Mummy Brown 30% 



Mars Brown 20% 



Buffy Citrine... , 10% 



Aniline Black , 10% 



Distribution of Colors as a Whole in Upper Ohio Drainage 

 (247 shells). 



Prouts Brown , ....30% 



Mummy Brown - 30% 



Mars Brown. •. 20% 



Buffy Citrine -io% 



Aniline Black.. ! 10% 



Distribution of Color as a Whole in Upper Ohio'Tributaries etc. 



Alleghney Alleghney Beaver ' Beaver Tusca. 

 Tribs. River Tribs. River River 



Prouts Brown 33 % 25 % 30%. 25 % 



Mummy Brown : ..35 % 50% 30% 25 % 75 % 



Mars Brown -15 % 25 % 25 % 25 %..... 



Buffy Citrine 10% 5% 25% 25% 



Aniline Black... :.... 5%... ........10% 



Distribution of Colors as a. Whole in L. Erie (16 shells).' 



Warm Blackish Brown - 20% 



Cinnamon Brown 20% 



Buffy Citrine! _ 20% 



