524 



PROCEEDINGS OF THE ACADEMY OF 



[1899. 



A NEW AMERICAN SPECIES OF ZONITOIDES. 



BY EDWARD G. VANATTA. 



Zonitoides nummus n. sp. 



Shell discoidal, shining, tfansluceut, waxen white. Spire very- 

 flat, composed of 3f rather convex slowly increasing whorls ; suture 

 impressed growth lines ^slight. The umbilicus is very wide, its 

 width contained in the greatest diameter of 

 the shell about 2^ times. Aperture irregu- 

 larly rounded-lunate, parietal callus thin. 



Alt. 0.5, greatest diam. 1.5, lesser diam. 

 1.33 mm. 



New Braunfels, Texas. 

 The type is in the collection of the Academy 

 of Natural Sciences, No. 68,834. 



This species has the color and texture of 

 Z. singleyanus Pils., but with the same num- 

 ber of whorls it is much smaller, being only 

 about one-half the size. It also differs from 

 Z. miniisculus Binn., in being much smaller 

 and flatter. 



It can easily be distinguished from the 

 other members of the Z. minusculus group 

 by the wide [umbilicus, discoidal form, and 

 the slowly increasing whorls. 



On examining cotypes and description of Z. Iceviusculus Sterki, I 

 find it is a synonym of Z. dngleyanus Pils. 



