94 BULLETIN 181, UNITED STATES NATIONAL MUSEUM 



tractively curved, strong ridges separated by spaces as wide as the 

 ridges. There are also deep pits at the umbilical keel, which are 

 more or less regularly disposed. The umbilical keel is rendered 

 rough by the incremental elements and the umbilical wall is marked 

 by rough axial riblets and lines of growth. Aperture circular, 

 oblique, decidedly protracted and angulated at the posterior angle; 

 outer lip thin, the inner somewhat thickened. Operculum typically 

 ptychocochlid. 



The specimen figured is one of two, U.S.N.M. No. 253665, from 

 Port Antonio, Portland Parish, Jamaica. It has 4.9 whorls and 

 measures: Height, 17.7 mm.; greater diameter, 25.3 mm.; lesser 

 diameter, 18.7 mm. 



A large series of specimens before me all come from the north coast 

 of Portland, ranging from Port Antonio westward. 



I have been unable to differentiate Chitty's Cyclotus portlandeTisis, 

 even subspecifically, from this species, 



PTYCHOCOCHLIS ADAMSI, new species 



Plate 14, Figubes 4-6 



Shell rather large, helicoid, the upper surface chestnut-brown ; the 

 lower, paler. Interior of aperture soiled white. The nucleus consists 

 of 1.5 well-rounded smooth whorls. The postnuclear whorls are marked 

 by rather weak somewhat retractively curved axial riblets, which are 

 rather distantly spaced. Beginning with the third postnuclear whorl, 

 weak nodules make their appearance, which extend from the appressed 

 summit to the periphery in a protractive, decidedly oblique slope. This 

 type of sculpture extends over only about half a turn, after which the 

 nodulation becomes irregularly disposed and practically disappears on 

 the last third of the last turn. The suture of the early whorls is very 

 strongly impressed. On the last 1.5 turns the summit of the turns be- 

 comes decidedly appressed and projects over the preceding turn so as 

 to form a strong ridge, which renders the suture less conspicuous. On 

 the last whorl there is a decided groove below this appressed portion. 

 Periphery well rounded. Base strongly rounded, openly umbilicated, 

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

 keel is separated by a decidedly impressed groove anteriorly. Posterior 

 to the keel more or less regularly disposed deep pits are present, while 

 the spaces between them extend as oblique short cords toward the 

 periphery ; they do not, however, reach the middle of the base. The 

 umbilical wall is marked by coarse riblets and lines of growth. Aper- 

 ture circular, oblique, protracted into a decided angle at the posterior 

 angle, where it joins the preceding turn as a slight shelf; peristome 

 thin on the outer lip, somewhat thickened on the inner. The oper- 

 culum is not quite typically ptychocochlid, the outer projection of the 



