THE CYCIjOPHORID LAND MOLLUSKS OF AMJERIOA 97 



openly umbilicated. The outer edge of the umbilicus is bounded by 

 a weak keel. The base is marked by rather strong incremental lines 

 and a series of oblique pits, which are not profound at the outer edge 

 of the umbilical keel. The umbilical wall is marked by low, rather 

 broad axial riblets and incremental lines. Aperture circular, oblique, 

 protracted into an angle at the posterior angle; peristome slightly 

 thickened. Operculum typically ptychocochlid. 



The type, U.S.N.M. No. 535969, was collected between Fort Au- 

 gusta and Port Henderson in St. Catherine Parish, Jamaica. It has 

 4.4 whorls and measures: Height, 11.3 mm.; greater diameter, 17.1 

 mm. ; lesser diameter, 13.2 mm. 



Two additional specimens from the same locality are a trifle larger. 



This species is nearest related to P. marianna^ from which it can 

 readily be separated by its broader umbilicus. 



PTYCHOCOCHLIS MARIANNA, new species 



Plate 15, Figxires 1-3 



Shell of medium size, helicoid, chestnut-brown, a trifle paler on 

 the underside. The nucleus consists of a single well-rounded, smooth 

 turn. Postnuclear whorls inflated, strongly rounded; the first is 

 marked by slender, retractively slanting, hairlike axial riblets, which 

 are as wide as the spaces that separate them. On the succeeding 

 turns these riblets become decidedly intensified and irregular as they 

 cross the ridges, nodulations, and pits. Beginning with the second 

 postnuclear whorl, oblique protractively slanting wrinkles make their 

 appearance. These ridges are separated by spaces not quite so wide 

 as the wrinkles. This sculpture continues to the last half of the 

 last turn, beyond which the wrinkles become irregularly disposed 

 and also decidedly irregular in size. Toward the end of this whorl 

 they become almost obsolete. Suture strongly impressed on the 

 early whorls, adnate on the last whorl. Periphery well rounded. 

 Base well-rounded, narrowly umblicated, the umbilicus provided with 

 a strong keel at its outer lunit. A deeply impressed groove sepa- 

 rates the keel from the umbilical wall. The keel is rendered de- 

 cidedly rough by the incremental elements. The base is marked by 

 scarcely p)erceptible indications of nodules. It also gives one the 

 impression of having obsolete spiral threads. The umbilical wall 

 is marked by moderately strong incremental lines. Aperture cir- 

 cular, decidedly oblique, protracted into an angle at the posterior 

 angle ; peristome thin. Operculum typically ptychocochlid. 



The type, U.S.N.M. No. 535970, was collected by Henderson at 

 Roaring River Falls, Ocho Rios, St. Ann Parish, Jamaica. It has 5 

 whorls and measures : Height, 17.0 mm. ; greater diameter, 21.2 mm. ; 

 lesser diameter, 16.3 mm. 



