764 PROCEEDINGS OF THE ACADEMY OF [DeC, 



Strebel and T. conspurcatella (Morel.). It is lower than the former 

 species, with a larger umbilicus, and higher than the latter, with the 

 umbilicus narrower. It unites the group of species referred to Acan- 

 thinula by von Martens with the typical forms of Thysanophora. 

 Named in honor of one of the authors of the volumes on mollusks in 

 the Mission Scientifique au Mexique. 



Thysanophora tatei Pilsbry. PI. XLIX, figs. 3, 3a, 36. 



Helix blakeana Tate, Amer. Jour, of Conch., V, p. 155, PI. 16, fig. 3 (1870). 



Not H. blakeana Newc, 1861. 

 Thysanophora tatei Pils. 



Shell depressed, discoidal, the spire but slightly convex; openly 

 umbilicate, the width of the umbilicus contained about 3f times in 

 the diameter of the shell; thin, slightly translucent, grayish corneous. 

 Sculpture of fine, rather close but somewhat irregularly spaced thread- 

 like rib-strise in harmony with growth-lines. Whorls 3^, convex, 

 slowly increasing to the last, which is double the width of the preceding, 

 rounded peripherally and beneath. Suture very deep and conspicuous. 

 Aperture shghtly oblique, round-lunate, about one-fourth of the circle 

 excised by the preceding whorl; lip thin and simple throughout, the 

 margins converging. Alt. 1.8, diam. 3 mm. 



Chontales forest, Nicaragua. 



The unique type is No. 58,065, A. N. S. P., collected by Ralph Tate. 



The name given by Tate to this species is preoccupied. It was 

 omitted from Crosse and Fischer's great work, and placed in the syn- 

 onymy of Pseudohyalina minuscula by von iMartens. It is related to 

 some undetermined species in the collection of the Academy from 

 northern South America, but has no very close relatives among Mexi- 

 can snails, so far as I know. The generic position of this snail is un- 

 certain, but it has more the appearance of Thysanophora than of any 

 Zonitid group. The thread-like rib-stria? are not cuticular, but more 

 like the striae of Pyramidula. 



BULIMULID^. 

 Bulimulus dealbatus Say. 



]\Iontcrey, State of Nuevo Leon. A slender form, closely mottled 

 and streaked. 

 Bulimulus dealbatus schiedeanus Pfr. 



Saltillo, Coahuila (S. N. Rhoads, 1899). The large typical form of 

 schiedeanus. 

 Bulimulus alternatus mariae Alb. 



^Monterey, State of Nuevo Leon; in chaparral near Victoria, Ta- 

 maulipas. Specimens from ^Monterey are like that from Laredo, Texas, 



