54 THE NAUTILUS. 



Symphynota costata Rafinesque. Tennessee river. Only dead 

 and poor ones found. 



Symphynota co?nplanata Barnes. Tornbigbee river, Columbus, 

 Miss. 



Margaritana monodonta Say. Tennessee river. Large numbers 

 were piled up by rocks, logs and in places on the river bank, where 

 the musk rats had opened them. The living ones were plen- 

 tiful under rocks in the shallow water, as many as two hundred 

 being found under one slab. 



Unto gibbosut Barnes. Tornbigbee and Tennessee rivers. 



Unio crassidens Lam. Tornbigbee and Tennessee rivers. 



Unio arctatus Conrad. Tornbigbee river, Columbus, Miss. 



Unio tetralasmus geometricus Lea. Yalabusha river, Grenada, and 

 a rill near Durant, Miss. 



Pleurobema hohtonensis Lea. Tennessee river, Florence, Ala. 



Pleurobema edgariana Lea. Tennessee river, Florence, Ala. 



Pleurobema tumescens Lea. Tennessee river, Florence, Ala. 



Pleurobema dolabelloides Lea. Tennessee river, Florence, Ala. 



Pleurobema decisa Lea. Tornbigbee river, Columbus, Miss. 



Pleurobema carta Lea. Big Black and Tornbigbee rivers. 



Pleurobema taitiana Lea. Tornbigbee river near Boligee, Ala. 



Pleurobema mix Lea. Tornbigbee river, Columbus, Miss. 



Pleurobema bulbosa Lea. Tornbigbee river, Columbus, Miss. 



Pleurobema nuculopses Conrad. Tornbigbee river, Columbus, Miss. 



Pleurobema aesopus Green. Tennessee river, Florence, Ala. 



Quadrula asper Lea. Tallahatchie, Yalabusha, Big Black and 

 Tornbigbee rivers. 



Quadrula plicata Say. Tennessee river, Florence, Ala. 



Quadrula perplicata Conrad. Yalabusha and Black rivers. 



Quadrula latecostata Lea. Tornbigbee river, Columbus, Miss. 



Quadrula heros Say. Tallahatchie, Yalabusha and Tennessee 

 rivers. 



Quadrula trapezoides Lea. Yalabusha, Big Black and Tornbigbee 

 rivers. 



Quadrula cylindrica Say. Tennessee river, Florence, Ala. 



Quadrula metanevra Raf. Tornbigbee and Tennessee rivers. 

 Common in both streams. 



Quadrxda intermedia Conrad. Tennessee river. 



Quadrula stapes Lea. Tornbigbee river, Columbus, Miss. 



