THE CYCLOPHORID LAND MOLLUSKS OF AMERICA 111 



the outer edge of the umbilicus. This keel on the first half of the last 

 whorl consists of oblique, protractive strong short ridges, which on 

 the last half disappear and give place to rough corrugations. Border- 

 ing the basal keel, on the outside, is a series of deep pits. The rest 

 of the base is marked by more or less continuous wrinkles, which have 

 a slightly oblique trend, being almost spiral in disposition. The um- 

 bilical wall is covered by strong axial ribs and fine incremental lines. 

 Aperture subcircular, decidedly oblique, with a conspicuous pro- 

 tracted angle at the posterior angle ; outer lip of the peristome thin, 

 the inner thickened, particularly so at the basal keel. Operculum 

 typically poterid. 



The specimen figured, U.S.N.M. No. 397856, was collected by Orcutt 

 5 miles from Black River on the road to Newmarket, St. Elizabeth 

 Parish, Jamaica. It has 5.25 whorls and measures : Height, 16.6 mm. ; 

 greater diameter, 26 mm. ; lesser diameter, 19.4 mm. 



The species appears to be restricted to southwestern St. Elizabeth 

 Parish, although we have it also from one station in Westmoreland 

 Parish, just across the border. In shape and in the sculpture of 

 the upper surface P. (P.) cornigatissima resembles most nearly 

 P. (P.) pdlescens (C. B. Adams), from which it can readily be dis- 

 tinguished by its much stronger basal keel and much stronger basal 

 sculpture. 



POTERIA (POTERIA) PALLESCENS (C. B. Adams) 

 Plate 16, Fiqubes 28-30 



1851. Cyclostoma pallescens C. B. Adams, Ann. Lye. Nat. Hist. New York, vol. 



5, p. 59. 



1852. Cuclotus pallescens Pfeiffeb, Monographia pneumonopomorum viventium, 



vol. 1, p. 27. 

 1898. Neocyclotus (Plectocyclotus) pallescens Kobelt and Moixendorff, Nachrb. 

 deutschen Malak. Ges., vol. 29, p. 138, reprint. 



Shell large, decidedly depressed-helicoid, almost planorboid, cov- 

 ered with a dark chestnut-brown periostracum. The nucleus consists 

 of about 1.5 moderately elevated, well-rounded, smooth turns. The 

 first postnuclear whorl is marked by weak, rather elevated axial rib- 

 lets, which are about as wide as the spaces that separate them. On 

 the succeeding turn these axial riblets become less regular, and wrin- 

 kles make their appearance on the upper surface. On the first part 

 of the last turn these wrinkles have both a decidedly oblique 

 protractive and retractive arrangement. On the last half of the 

 last whorl they are more inclined toward a protractive arrange- 

 ment. These wrinkles do not quite extend to the summit of the whorls 

 but begin at the anterior termination of the anterior fourth between 

 the summit and suture, the summit being marked by rough lines of 

 growth only. Suture strongly impressed, even on the last whorl. 



