84 PROCEEDINGS OF THE ACADEMY OF [1889. 



form I find in the museum of the Academy, collected by Mr. Henry 

 Hemphill. 



Zonites singleyanus Pilsbry. Proc. A. X. S. Philada., 1888, PI. xvii, figs. m,m,m. 



►Shell minute, broadly umbilicate, planorboid, the spire scarcely 

 perceptibly exserted ; subtranslucent, waxen white, shining, smooth, 

 under a strong lens seen to be slightly wrinkled by growth-lines ; 

 whorls three, rather rapidly increasing, separated by well-impressed 

 sutures, convex, the apex rather large ; body-whorl depressed, 

 slightly descending, indented below around the umbilicus ; aperture 

 small, semilunar, oblique ; peristome simple, acute. Umbilicus nearly 

 one-third the diameter of the shell, wide, showing all the whorls. 



Alt, 1, diam. 2 mill. 



New Brannfels, Comal Co., Texas. 



Allied to Z. minusculus, but much more depressed, more shining, 

 smoother, smaller, with broader umbilicus and a complete whorl 

 less than minusculus. 



This species, one of the most 'distinct of the smaller forms of 

 Hyalina, was communicated to me by Mr. J. A. Singley, in whose 

 honor it is named. I have also found a few specimens among the 

 shells collected by myself in central Texas, during the winter of 

 1885-'86. With Z. singleyanus at New Braunfels are found 

 quantities of Z. minusculus. The latter species exhibits some varia- 

 tion, being often more depressed than most northern specimen. This 

 depressed form has been noticed in Mexico by Strebel,* who pro- 

 poses for Z. minusculus the new generic title of Chanomphalus, which 

 of course is completely synonymous with Pseudohyalina Morse. 

 1864, and this again is not different enough from Hyalina to warrant 

 the erection of a new genus or sub-genus. There is some variation 

 in the width of the umbilicus in Texan specimens of Z. minusculus, 

 but I have not seen specimens with it so wide as Dr. Dall indicates 

 for his var. alachuana, from Florida. H elegantulus Pfr. is about 

 the size and form of my Zonites singleyanus, but it is a strongly sculp- 

 tured species. 



It may not be out of place here to note the fact that the Helix 

 (Polygyra) hippocrepis Pfr. has been rediscovered by Mr. Singley, 

 near New Braunfels ; as typical examples sent me attest. This 

 species has been heretofore known by but one specimen in America 



* Vide Beitrag zur Kenntniss der Fauna mexikanischer Land und Siisswasser 

 Conchylien, Theil iv, p. 19, pi. iv, fig. 10. (1880.) 



