1894.] NATURAL SCIENCES OF PHILADELPHIA. 25 



Co., iNId., 64,808. Potomac River at Hancock, Md., 64,810. 

 Town Creek, AUeoheny Co., Md., 64,807. Flintstone Creek at 

 Flintstoue, Md., 64,815. Evitt's Creek, near Cumberland, Md., 

 64,816. Potomac River, o miles below Cumberland, 64,811. 

 Patterson '.s Creek, Mineral Co., W. Va., 64,812. Potomac River, 

 at Cherry Run, W. Va., 64,81o. A small creek flowing into 

 LittTe Cacapon River, Ham})shire Co., W. Va. , 64,817. South 

 Fork Shenandoah River, near Luray, Va., 64,819. Also York 

 Furnace, Pa. (Stone). 



Que lot, 64,807, shows a strong tendency toward the obeseness so 

 characteristic of the transition forms between heterostropha and an- 

 cillaria found at Philadelphia and Washington. All of the others 

 are very near the type of heterostropha. 



Family VIVIPARIDJE. 



Genus CAMPELOMA Rafinesque. 



C. decisum Say. 



Potomac River at Hancock, i\[d., 64,751. Potomac River at 

 Cherry Run, W. Va., 64,752. Typical at both localities. Stone 

 collected it at York Furnace, York Co., Pa., with Lioplax subcari- 

 iiata. 



Family AMNICOLIDJE. 

 Genus AMNICOLA G. & H. 

 A. limosa Say. 



Very numerous in the canal at Hancock, Md., 64,755. Coneco- 

 cheague River, west of Hagerstown, Md., 64,756 (small form). Also 

 found at York Furnace, York Co., Pa., by Witmer Stone. 



Genus GILLIA Stimp. 

 G. altilis Lea. 



Canal at Hancock, Md., 64,782. Potomac River, at Cherry 

 Run, \y. Va., 64,781. 



An abundunt species throughout the drainage of the Chesapeake 

 and Delaware Bays. Stone found it at York Furnace, York Co., 

 Pa. 



o 

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