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Vol. 5, p. 423-426. Octobek 10, 1931. 



Occasional Papers 



OF THE 



Boston Society of Natural History. 



THREE NEW TERRESTRIAL SNAILS FROM YUCATAN. 

 BY JOSEPH BEQUAERT AND W. J. CLENCH. 



The snails described below were collected during an expedition 

 to Yucatan in 1929, carried on jointly by the Carnegie Institution 

 of Washington, D. C, and the Department of Tropical Medicine 

 of Harvard Medical School, under the leadership of Dr. George 

 C. Shattuck. The species will be figured in a forthcoming com- 

 prehensive account of the non-marine mollusks of Yucatan. 



Spiraxis (Volutaxis) may a, sp. no v. 



Description of shell. — Small, turrite, imperforate, thin and translucent. 

 Color white, glassy. Whorls 73^, quite convex, regularly increasing in size, 

 the last whorls three-sevenths of the total length of the shell. Spire regularly 

 tapering to the obtuse summit. Aperture obHque, elliptical, short (about 

 two-sevenths of the total length of the shell). Peristome simple, acute, thin, 

 well rounded and slightly arched forward. Columella thin, nearly vertical 

 and non-truncate, weakly but distinctly twisted. Sutures deeply impressed, 

 not margined. Surface shiny, with fine, regularly spaced axial riblets, much 

 narrower than their intervals (each riblet about one-fourth the width of an 

 interval); the interval spaces have exceedingly fine, microscopic growth lines; 

 the last whorl with approximately 40 riblets; the embryonic whorls (first one 

 and a half) smooth. 



Length Width Length of Aperture 



4.8 1.6 1.2 mm. Holotype 



4.1 1.5 1.0 Paratype 



Holotype. — M. C. Z. no. 85799, from Chichen Itzd, Yucatan, collected by 

 J. Bequaert, June, 1929. 



Paratype. — A. N. S. Phila.; data as above. The two specimens were found 

 dead. 



Remarks. — Dr. Pilsbry has kindly compared this minute snail 

 with the large series of Spiraxis at the Academy of Natural 

 Sciences of Philadelphia. Its only close relative appears to be 

 S. streheli Pilsbry (1907, Man. of Conch. (2) 19, p. 27, pi. 6, fig. 

 27-28), from Texolo, V era Cruz. Comparing it with paratypes 



I OCT 2 1 1931 1 



