THE CYCLOPHORITD LADSTD MOLLIISKS OF AMEiRIOA 89 



protracted ridges, which are less than half the width of the spaces 

 that separate them. Suture strongly impressed. Periphery of the 

 last whorl well rounded. Base broadly openly umbilicated, the 

 outer edge of the umbilicus being marked by an obsolete cord. The 

 base is marked by rather closely spaced, broad, retractively curved, 

 moderately elevated ridges, which are best developed on the early 

 portion of the last turn. On the last portion of the last turn these 

 ridges become obsolete. The umbilical wall is marked by rough 

 riblets and incremental lines. Aperture circular, rather effuse at 

 the junction of the outer and basal lip, and slightly angulated at the 

 posterior angle ; peristome tliin. Operculum typically ptychocochlid. 

 The type is one of six specimens. No. 174135, in the collection of 

 the Academy of Natural Sciences of Philadelphia. It was collected 

 by H. Burrington Baker at Belretiro, Manchester Parish, Jamaica. 

 It has 4.5 whorls and measures : Height, 11 mm. ; greater diameter, 

 17.4 mm.; lesser diameter, 13.0 mm. 



PTYCHOCOCHLIS TAYLORI. new species 



Plate 13, Figubes 31-33 



Shell of medium size, varying in shape from helicoid to depressed- 

 helicoid, covered with a thin olivaceous periostracum. The nucleus 

 consists of a single smooth, well-rounded turn. The postnuclear 

 whorls are strongly rounded; the first 1.5 are marked by rather weak, 

 slender axial riblets which are rather distantly spaced. On the suc- 

 ceeding turn the axial riblets become irregular, sinuous, and almost 

 narrowly lamellose. Beginning with the second postnuclear whorl 

 and extending to the last half of the last turn, very oblique, protac- 

 tively slanting ridges are present, which are about as wide as the 

 spaces that separate them. On the last half of the last turn these 

 ridges become very irregular and have the nodules all arranged in 

 a retractive position. Suture well impressed. Periphery well 

 rounded. Base well rounded, openly, rather broadly umbilicated 

 with a rather strong keel at the outer limit of the umbilicus. The 

 early part of the base bears quite strong nodulations, which gradu- 

 ally become weaker toward the end. The umbilical wall is marked 

 by numerous, closely spaced, slender hairlike riblets. Aperture sub- 

 circular, oblique, slightly protracted and angulated at the posterior 

 angle; outer peristome thin, the inner peristome is rather thickened. 



The type, U.S.N.M. No. 356032, was collected by C. B. Taylor in 

 Upper Clarendon Parish, Jamaica. It has 4.4 whorls and measures : 

 Height, 11.8 mm.; greater diameter, 17.0 mm.; lesser diameter, 13.1 



mm. 



