THE NAUTILUS. 69 



The present species is named after Mr. H. E. Sargent, who has 

 assiduously collected small mollusca, and has secured some good lots 

 of this Pisidium. 



THE AMEEICAN PHYSJE. 



BY O. A. CRANDALL, SEDALIA, MO. 



Physa forsheyii Lea. 



Sub-species Physa forsheyii grosvenorii Lea. 



This species was discovered near Ruterville, Texas, in 1864. The 

 description calls for six whorls, but I have examined cotypes in the 

 Academy of Sciences in Philadelphia, and nearly a hundred exam- 

 ples from eight different localities, and have been unable to find a 

 single one having more than five, so I concluded that five is the 

 proper number. 



This is a small shell, not exceeding f inch in length, and dis- 

 tinguished by its sub-fusiform shape, exserted spire, deeply impressed 

 sutures, smooth but not shining surface. Nearly all the adults are 

 covered with microscopic transverse strige, which give the surface a 

 dull appearance. Bi-annuan. 



Physa grosvenorii Lea, also described in 1864, belongs here as a 

 variety. I have collected it in many different places, and have no 

 hesitancy in referring it to this species. The only difference I can 

 discover between this and P. forsheyii is that it is smaller, shorter, a 

 little more inflated, more robust, and of a darker color. Some of the 

 young shells are highly polished, but the adults have the same dull 

 appearance as the species form, and are dark yellowish horn-color. 

 It is a very pretty shell, uniform in size, color and general outline. 



In the middle of January I found some of these little shells under 

 some leaves in a spring brook near Sedalia, Mo., where they hiber- 

 nated for the winter. The aperture, instead of being closed by a film 

 as in land shells, was filled with dirt and sand, mixed with the viscid 

 exudations from the body, forming a cement one-eighth inch thick, 

 which I found quite difficult to remove without injury to the shell. 



The species form is distributed over Texas and Louisana, but 

 farther north, through Arkansas, Indian Territory, Southern Kansas 

 and Missouri, as far north as the central part of the state, it takes 

 the form of P. grosvenorii. 



Forms : Physa whitei, Lea. 



