70 JOURNAL OF THE 



over a radius of lo or 15 miles, and is much esteemed for 

 its good working qualities. The whole thing is rude in 

 construction and arrangement and is entirely exposed to 

 the weather. The water supply is abundant and no 

 attempt is made to economize in that particular. Suitable 

 ore is found as friable magnetite in the near neighborhood, 

 but the forge is worked only as the demand may arise. 



NOTES ON THE FERTILITY OF PHYSA HET- 

 EROSTROPHA SAY. 



BY W. L. POTEAT. 



In the essay on the "Duration of Life" Weismann 

 remarks that while the length of life of many molluscan 

 species is well known, "any exact knowledge is still want- 

 ing concerning such a necessary point as the degree of their 

 fertility."* Binney remarks of the family Limnseidae, to 

 which our snail belongs: "From the fact of my finding 

 young individuals only in the spring and numerous dead 

 full-grown shells during the late autumn and winter, I pre- 

 sume they arrive at maturity in one season. "f Of Physa 

 heterostropha in particular he says that it deposits eggs the 

 beginning of May. 



In view of these statements I have thought it perhaps 

 worth while to record in this place some observations made 

 by me in the year 1886. 



On the 8th of March I collected from a marsh near 

 Wake Forest two specimens of Physa heterostropha Say.t 



■^•Heredity, p. 14. 



tl^and and Fresh-water Shells of N. Amer., p. 23, Vol. VII, Smiths. Misc. Coll. 

 jKindly determined for me later by Dr. Stearnes, of the National Museum at Wash- 

 ington. 



