212 PROCEEDINGS OF THE ACADEMY OF [DeC, 



MOLLUSCA FROM CENTRAL AMERICA AND MEXICO. 

 BY HENRY A. PILSBRY. 



Most of the forms described herein were collected by Mr. A. A. 

 Hinkley during two visits to Guatemala. A few are added from 

 various other localities, collected by Mr. S. N. Rhoads and others. 



With the exception of Neritilia, a peculiar Neritid mollusk with 

 a more specialized radula than others of its family, the species belong 

 to genera already well represented in Mexico and Central America. 

 Salasiella hinkleyi n. sp. Fig. 2. 



The shell is cylindric with tapering spire, glossy, finely, arcuately 

 striate, with numerous irregularly spaced grooves indicating former 

 peristomes. First three whorls rather slowly widening, after which 

 the suture descends more rapidly, oblique to the previous whorls, 

 each succeeding whorl at least double the width of that above it. 

 The last whorl is flattened laterally. Aperture half the length of 

 the shell. Outer lip arching very strongly forward in the middle. 

 Columella very deeply concave above the truncation. 



Length 8.5, diam. 3 mm.; 5^ whorls. 



Mountain side near the Tamosopo Sugar Company's place, San 

 Luis Potosi. Also at El Abra. 



This species changes so much with age that without a good series 

 one would not readily connect the half-grown and the mature stages. 

 After the third whorl the suture descends very rapidly, and the 

 aperture becomes shorter in comparison with the total length. 

 Moreover, the deep, arcuate grooves which characterize the fully 

 adult shell are far weaker and less numerous in specimens of 6 mm. 

 length or smaller. 



It is closely related to S. joaquinoe Strebel, but adult specimens 

 of the same length have a half whorl more and a shorter aperture. 

 Probably the specimens from Diente, near Monterey, Nuevo Leon, 

 referred to joaquince are immature S. hi7iJdeyi. 



16 specimens were taken at El Abra, the largest measuring, length 

 6, diam. 2 mm. The aperture is decidedly over half the total length 

 at this stage. It is quite possible that the largest shell from the 

 type locality (fig. 2) is an exceptionally large and old individual. 



