THE CYCLOPHORID LAND MOLLUSKS OF AMERICA 133 



The verge is situated on the back of the neck behind the tentacles. 

 It is swollen basally and provided with a seminal groove and a very 

 short simple terminal appendage. 



KEY TO THE WEST INDIAN SPECIES OF THE SUBGENUS AUSTROCYCLOTUS 



Sculpture very strong and filelike rugatum 



Sculpture not as strong or filelike. 



Shell averaging more than 20 mm. in diameter vincentinum 



Shell averaging less than 15 mm. in diameter grenadense 



APEROSTOMA (AUSTROCYCLOTUS) RUGATUM (Guppy) 



Plate 17, Figukes 10-12 



1864. Cyclotus rugatus Guppy, Ann. Mag. Nat. Hist., ser. 3, vol. 14, p. 246. 



Shell of medium size, depressed-helicoid, openly, moderately, 

 broadly, umbilicated, covered by a golden-brown periostracum. Nu- 

 clear whorls 1.5, well rounded, smooth, forming a moderately elevated 

 spire. Postnuclear whorls inflated, strongly rounded, strongly in- 

 bent at the suture excepting the last fifth of the last turn, which 

 is marked by rather strong, decidedly retractively curved axial rib- 

 lets. On the last whorl the riblets are replaced by more or less 

 zigzagging ridges separated by spaces equaling them. This zig- 

 zagging produces a filelike resemblance. On the last fifth of a 

 turn these elements become much disturbed and finally obsolete. 

 Suture strongly impressed; periphery strongly rounded. Base in- 

 flated, strongly rounded, and marked by the continuation of the 

 sculpture at the spire. Umbilical wall marked by closely spaced 

 axial cords. Aperture oblique, almost circular, slightly angulated 

 at the posterior angle. Peristome simple. Operculum typically 

 austrocyclotid. 



I collected the specimen described and figured, U.S.N.M. No. 

 390108, at Brigham Hill, Central Range, Trinidad, on September 2, 

 1928. It has 4.4 whorls and measures: Height, 12.9 mm.; greater 

 diameter, 17.5 mm. ; lesser diameter, 15.6 mm. I took three additional 

 specimens, U.S.N.M. No. 394005, on Verdant Vale, about 4 miles north 

 of Arima, Trinidad, on September 3, 1929. 



This species is much more robust and rotund, with the sculpture 

 much coarser and rougher, than A. (A.) grenadense (Shuttleworth). 



APEROSTOMA (AUSTROCYCLOTUS) VINCENTINUM (Pilsbry) 



Plate 17, Figubes 1-3 



1935. Poteria vincentma Pilsbby, Proc. Acad. Nat. Sci. Philadelphia, vol. 87, 

 p. 4, pi. 1, figs. 2, 2a. 



Shell rather large, depressed-helicoid. Nuclear whorls almost 2, 

 smooth, well rounded. Postnuclear whorls marked by numerous, 



