THE CYCLOPHORID LAND MOLLUSKS OF AMElRIClA 91 



of a single well-rounded, smooth turn. Postnuclear whorls well 

 rounded ; the first is marked by slender, decidedly retractively curved, 

 rather closely spaced axial riblets, which are fairly strong. The 

 succeeding turns also have axial riblets, which are less regular, and 

 quite irregular on the last whorl, where they are almost lamellose. 

 In addition to this, beginning with the second postnuclear whorls, 

 there are strong, decidedly retractively slanting ridges that do not 

 extend on the posterior fourth of the turns. These ridges are not 

 quite so wide as the spaces that separate them, and they become 

 obsolete on the last third of the last whorl, where they are replaced 

 by less strong irregular nodulations. Suture strongly impressed. 

 Periphery well rounded. Base well rounded, openly umbilicated, the 

 umbilicus bounded by a strong keel, which is inpinched on both 

 sides. The base is marked on the early portion of the last turn by 

 oblique, retractively slanting ridges, which are replaced on the last 

 half of the turn by irregular wrinkles. The umbilical wall is marked 

 by riblets and fine lines of growth. Aperture circular, oblique, 

 slightly protracted into an angle at the posterior angle. Peristome 

 thin. Operculum typically ptychocochlid. 



The type, U.S.N.M. No. 535967, is one of a series of specimens 

 collected by Orcutt at Balaclava, St. Elizabeth, Jamaica. It has 

 4.8 whorls and measures: Height, 14.0 mm.; greater diameter, 19.8 

 mm. ; lesser diameter, 15.2 mm. 



A host of specimens before me appear to confine this species to 

 the Cockpit region of northern St. Elizabeth Parish. 



PTYCHOCOCHLIS CLAPPI, new species 



Plate 14, Figures 19-21 



Shell very large, helicoid, covered with a chestnut-brown periostra- 

 cum. The nucleus consists of 1.5 well-rounded smooth turns. The 

 postnuclear whorls are well rounded, the early ones separated by a 

 well-marked suture, and the later ones appressed at the summit. 

 The first 1.5 nuclear whorls are marked by slender, slightly retract- 

 ively curved axial riblets, which are about as wide as the spaces that 

 separate them. Beyond this the nodular ridges gradually make their 

 appearance. These are rather irregular, that is they begin at the 

 summit as retractive elements, then near the middle of the whorl bend 

 forward into protractive ridges, thus producing a somewhat arrow- 

 pointed cone-in-cone effect. This arrangement disappears on the 

 last half of the last turn, where the nodulations become irregular 

 and quite obsolete. On the last fourth of the last whorl, spiral 

 threads make their appearance. The last whorl is strongly con- 

 stricted below the summit, which causes the posterior portion to 

 appear decidedly appressed to the preceding turn. Periphery well 



