102 BTJLLETiEN 181, inSTITEiD STATES NlAmoaSTAIL MUStEUM 



shaped effect. On the last whorl the sculpture becomes irregular and 

 on the last half of the last turn quite obsolete. Suture strongly im- 

 pressed on the early turns ; on the last whorl the summit of the turn is 

 appressed to the preceding turn and the suture is less conspicuous. 

 Periphery strongly rounded. Base moderately broadly umbilicated, 

 with a strong keel marking the outer limit of the umbilicus. This keel 

 is strongly inpinched on the umbilical margin and less so on the basal 

 margin. It is rendered rough by the incremental lines. The base does 

 not have pronounced tubercles but merely here and there an indication 

 thereof. The umbilical wall is marked with moderately strong riblets 

 and incremental lines. Aperture circular, the posterior angle pro- 

 tracted into an angulation ; outer lip of the peristome thin, the inner 

 slightly thickened. Operculum typically ptychocochlid. 



The type, U.S.N.M. No. 535972, was collected by Henderson at Mon- 

 tego Bay, St. James Parish, Jamaica. It has 4.7 whorls and measures : 

 Height, 15.7 mm. ; greater diameter, 21.6 mm. ; lesser diameter, 16.2 mm. 



The species seems to be confined to the region about Montego Bay, 

 where it appears to be rather abundant. 



PTYCHOCOCHLIS VENDREYSI, new species 



Plate 15, Figtjbes 36-38 



Shell rather large, dark chestnut-brown, with a little paler zone 

 at the suture and a rosy tinge on the early whorls. The interior of the 

 shell is bright chestnut-brown with a reddish tinge, the edge of the 

 peristome being a little paler. The nucleus consists of a little more 

 than a single turn, which is well rounded and smooth. The post- 

 nuclear whorls are inflated and well rounded; the first turn is marked 

 by slender, retractively curved axial riblets; the next, in addition to 

 the axial riblets, which become almost lamellose on the succeeding 

 turns, is marked by decidedly protractively curved, low, weakly devel- 

 oped ridges which are separated by equally inconspicuous impressions. 

 On the remaining turns this sculpture becomes obsolete and the surface 

 is merely rendered slightly rough by a few pits and weak nodules. 

 The last portion of the upper surface of the last whorl bears indica- 

 tions of poorly developed spiral threads. Suture of the early whorls 

 well impressed; the last whorl has the summit appressed and the 

 suture thereof not so strongly emphasized. Periphery well rounded. 

 Base well rounded, openly umbilicated, with a strong keel at the outer 

 edge of the umbilicus, which is strongly inpinched on its mnbilical 

 margin and feebly impressed on the outer edge. The base, in addi- 

 tion to incremental lines, has some indications of spiral threads and 

 an occasional little nodule. The umbilical wall is marked with axial 

 riblets and incremental lines. Aperture circular, decidedly oblique, 



