4 PKOCEEDINGS OF THE ACADEMY OF [Jan., 



Guppya costaricana n. sp. Fig. 2. 



Alajuela, 3200 ft. Type No. 105285, A. N. S. P. 



The shell is minutely perforate, globosely conic, very fragile, light 

 yellow; outlines of the spire are perceptibly concave, the periphery 

 bluntly carinate. The surface is very glossy, marked with weak 

 growth-wrinkles, and under the microscope a very fine, close, ver- 

 tical striation and minute spiral lines almost equally close are seen 

 on the second to fourth whorls, very weak on the fourth. The 

 apex is rather acute. The whorls are strongly convex; base very 

 convex, impressed around the oblique perforation. The aperture 

 is broadly lunate. Columellar margin is dilated upward. 



Alt. 5, diam. 6.1 mm.; 5f whorls. 



The pedal grooves are well-marked, rising at the tail. There 

 is a wedge-shaped caudal pore, a short, blunt horn above it. The 

 top of the tail is rounded. Sole narrow, tripartite. 



Fig. 1. Guppya calverti. Fig. 2. Guppya costaricana. Fig. 3. Guppya c. elatior. 



This species is closely related to G. trochulina (Morel.), of which 

 Helix selenkai Pfr. has been shown to be a synonym.'' It differs 

 by the slightly concave outlines of the spire, the greater convexity 

 of the individual whorls, the higher first whorl and the microscopic 

 sculpture, the vertical striae being much more distinct and the 

 spirals closer. In topotypes of selenkai from Dr. Berendt, the 

 original collector, the spirals are far more widely spaced (as noted 

 by von Martens also for a paratype of trochulina) , and they continue 

 on the last whorl, while the vertical striation is so weak that it has 

 not been noticed by any of the authors who have treated of trochu- 

 lina or selenkai. 



The Canal Zone species of this group, Guppya hrowni Pils., has 

 the straight contour of trochulina, but it differs by the very distinct 

 and beautiful microscopic sculpture. 



^ BlOLOGIA, p. 120. 



