44 THE NAUTILUS. 



from magnified by being smooth or nearly so, some being nearly as 

 smooth as viviparus. They are found under rocks in the swift 

 current of the stream. Both forms, magnified and angulata, vary 

 greatly in color from a light horn to a dark purple. 



Campeloma ponderosum Say. Tennessee River, Decatur ; Coosa 

 River, Wilsonville ; Fort William Shoals and AVetumpka. 



0. coarctatum Lea. Black Warrior River, Warrior ; Tallapoosa 

 River, Tallassee. 



C. decisum Say. Tennessee River, Decatur. 



0. nolani Tryon. Coosa River, Wetumpka. 



Lioplax cyclostomatiformis Lea. Black Warrior River, Warrior j 

 Coosa River, Fort William Shoals and Wetumpka. 



FAMILY VALVATIDA;. 



Valvata bicarinata Lea. Coosa River near the railroad bridge, 

 Farmer, Ala., but three specimens found. 



FAMILY 



Somatogyrus aureits Tryon. Coosa River, Fort William Shoals, 

 rare. 



S. constricius Walker. Coosa River, Wetumpka and Wilsonville, 

 very few; nearly always found on the underside of the rocks associ- 

 ated with S. coosaensis and S. hinkleyi, very seldom more than one on 

 the same rock. The light color, eroded spire and deep suture made 

 them easily noticed among other species. 



S. coosaensis Walker. Wetumpka, Fort William Shoals; common. 

 On rocks in swift water; sometimes 25 to 30 were seen together. 



S. crassus Walker. Wetumpka and Fort William Shoals ; not 

 plentiful. 



S. hinkleyi Walker. At all localities in the Coosa River, One 

 specimen supposed to be from the Tallapoosa River above Tallassee, 

 was probably mixed with S. pilsbryanus by accident. 



S. nanus Walker. Very plentiful at Fort William Shoals. They 

 literally covered the rock-bed of the stream in favorable situations, 

 showing up very plainly through the clear water, but owing to the 

 swift current it was difficult and tedious collecting them. 



S. obtusus Walker. Coosa River, Farmer, above the railroad 

 bridge, found among the drift in a stagnant pool, made by the low 

 stage of water. 



