120 BULLETIN 181, UNITEiD STATES N1ATT0!N1AL MUSEUM 



has 5.1 whorls and measures : Height, 22.7 mm. ; greater diameter, 31.0 

 mm. ; lesser diameter, 23.1 mm. 



The large size will readily distinguish this species from all the 

 other known Cyclobakerias. 



POTERLA. (CYCLOBAKEKIA) NANA, new species 



Plate 16, Figures 19-21 



Shell quite small, helicoid, covered with a chestnut-brown peri- 

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

 turn. The postnuclear whorls are inflated, strongly rounded, and 

 marked by slightly retractively slanting, closely spaced axial riblets, 

 which at first are hairlike, and which on the last whorl become almost 

 sublamellar. Beginning with the fourth whorl, protractive zigzag 

 ridges make their appearance, which fade out toward the summit. 

 The last whorl is decidedly appressed, and the portion that extends 

 up on the preceding turn has a constriction bounding it which makes 

 it appear cordlike. Suture strongly impressed, less so on the last 

 turn on account of the appressed summit. Periphery well rounded 

 and marked by the continuation of the zigzag cords. Base inflated, 

 strongly rounded, rather narrowly umbilicated, and marked by strong 

 protractive cords which are about as wide as the spaces that sepa- 

 rate them and radiate from the umbilical keel toward the base. The 

 posterior portion of the base is marked by the feeble continuation 

 of the sculpture of the upper portion of the whorl. It also shows 

 indications of spiral threads. The umbilical wall is marked by 

 feeble riblets and numerous threadlike incremental lines. Aperture 

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

 angle ; peristome of the outer lip protracted, thin ; that of the inner 

 lip somewhat thickened. Operculum typically cyclobakerid. 



The type, U.S.N.M. No. 535979, is one of a series collected by 

 Orcutt at Cousins Cove, Hanover Parish, Jamaica. It has 4.5 whorls 

 and measures: Height, 11.8 mm.; greater diameter, 17.0 mm.; lesser 

 diameter, 12.6 mm. The species appears to be restricted to the north- 

 west coast of Hanover Parish. 



POTERIA (CYCLOBAKERIA) DENTISTIGMATA (Chitty) 



Plate 17, Figuees 34-36 ; Plate 42. Figures 1-3 



1857. Cyclotus dentistigmatus Chitty, Proc. Zool. Soc. Loudon, vol. 25, p. 154. 

 1898. Neocyclotus (Plectoci/clotus) dentist igm dins, Kobelt and Mollendorff, 

 Nachrb. deutschen malak. Ges., vol. 29, p. 138, reprint. 



Shell of medium size, helicoid, covered with a chestnut-brown 

 periostracum ; nuclear whorls scarlet red. The nucleus consists of 1.5 

 inflated, well-rounded, smooth turns. The postnuclear whorls are 



