1889.] NATURAL SCIENCES OF PHILADELPHIA. 89 



Cedar Creek, Hudson Co. (G. C. Heron) and Guadalupe River, 

 Comal Co., Texas. (J. A. Singley.) 



The shells from Comal Co. are smaller than the specimen figured, 

 but are precisely the same in form and coloration. S. cubense is a 

 differently-proportioned shell, its valves are more convex, and the 

 dark spots are small. 



S. meridionale and S. maculatum have similar large color-blotches, 

 but they are both decidedly larger species and differ from S. singleyi 

 in outline. This is the first species of the group Limosina which 

 has been found within the borders of the United States. 



