May, 1803.] MOLLUSKS OF THE DEATH VALLEY EXPEDITION. 273 



Helix (Praticola) beilandieiiatia Mof. 



Nueces Bay, San Patricio County (Mus. No. 123586), December, 1891, and Matagorda 

 Peninsula., Texas (Mus. No. 123387). .January 30, 1892, William Lloyd. 



Numerous examples from the former and two from tlie latter locality. 



Helix (Mesodon) tliyroides Say. 



Natividad River, Texas (Mus. No. 123588), William Lloyd, January 4, 1802. 



Four fine specimens, one immature; two with a small parietal tooth, 

 all of a dark amber horn color, and lustrous glazing. These beautiful 

 examples, while fully as elevated as the larger of the three figures (337) 

 in Biuuey's Manual of American Laud Shells, Bull. U. S. National 

 Museum, No. 28, p. 315 (M. huceulentus), are somewhat larger and slightly 

 angulated at the periphery. The umbilicus is covered, peristome mod- 

 erately thick, size of shell considered. These are links in the chain of 

 connection of the typical tliyroides with the huceulentus aspect. 



Helix (Polygyra) texasiana Mor. 



Natividad River, Texas (Mus. No. 123589), William Lloyd, January 4, 1892. 



Two examples of this somewhat puzzling group. A comparison of 

 Bland's triodontoides and Pfeiffer's Mcruris creates the suspicion that 

 a large geographical series might result in placing two of the three 

 species in the waste basket of synonymy. 



Helix (Polygyra) bicruris Pfr. 



Brownsville, Tex. (Mus. No. 123594) ; Mouth of Eio Grande, Texas. (Mus. No. 

 123168). William Lloyd. 



Two examples, mature and perfect, from the first and one from the 

 last named locality. Heretofore credited to Mexico. 



Pupa (Vertigo) pentodon Say. 



Vegas Valley, Lincoln Couuty, Nev. (Mus. No. 123590), Vernon Bailey, March 7, 1891. 



The dozen or more examples of this tiny shell were detected by Mr. 

 Bailey at Cottonwood Springs at the east base of the Charleston Moun- 

 tains, otherwise known as the Spring Mountain range, of which the 

 principal elevation is called Charleston Peak. The region is in the most 

 southern part of Nevada. This species has not before been detected 

 so far to the west or anywhere within the vast area of the Great Basin 

 or the Pacific States. 



Bulimulus dealbatus Say. 



Monterey, Mexico (Mus. No. 123909), William Lloyd, February, 1891. 



Four characteristic examples, mature and immature; dead shells. 

 Bulimulus alternatus Say. 

 Hidalgo, Tamaulipas, Mexico (Mus. No. 123592); Brownsville (Mus. No. 123691); 



aud Nueces Bay, San Patricio County, Tex. (Mus. No. 123593), William 



Lloyd, December, 1891. 



The four Mexican specimens are very fine examples of this species 

 and well illustrate the propriety of Say's specific name. The alterna- 

 tion of the irregular, somewhat diaphanous, longitudinal bands with 

 others of a more opaque aspect is quite striking. The examples from 

 the Texan localities are of the ordinary aspect. 

 12731— No. 7 18 



