176 BULLETIN 192, UNITED STATES NATIONAL MUSEUM 



longitudinal and spiral threads which are not much elevated, subvarici- 

 form, shining, flesh colored with a violet tinge. Spire regularly attenu- 

 ated, sublate-truncate. Suture simple. The whorls remaining 4, convex, 

 the last solute anteriorly. Aperture subvertical, oval; peristome double, 

 the inner continuous, expanded and adnate to the outer; the outer flat, 

 subequal, a little narrower on the umbilical wall and subreflexed. Oper- 

 culum? Length, 30.0 mm.; diameter, 16.0 mm.; aperture with the peri- 

 stome, 15.5 mm. long and 13.5 mm. broad. 



The single specimen of this beautiful species is easily differentiated 

 from Cyclostoma habichii Weinland by the free last whorl as well as 

 the difference in rotundity of the whorls. 



I have not been able to satisfy the above description with any of the 

 material from the western part of the south peninsula of Haiti and 

 therefore refer it to Incertipoma. 



INCEBTIPOMA DIAPHANUM, new species 



Plate 30, Figure 6 



Shell elongate-ovate, very thin, translucent, with rather distantly 

 spaced, squarish or rounded spots, which are arranged in both axial and 

 spiral series. Of these spots five are present on the last whorl between 

 the summit and the periphery and two on the base. The outer peristome 

 shows these spots as rays. Nuclear whorls about 2, inflated, strongly 

 rounded, microscopically granulose, forming a small apex. Postnuclear 

 whorls inflated, strongly rounded, slightly shouldered at the summit, and 

 marked by weak, retractively curved axial riblets which are low, rounded 

 and very regularly spaced. Of these, 128 are present on the last turn. 

 The spiral sculpture consists of weak threads about equaling the riblets 

 in strength. Of these, 25 are present between the summit and the pe- 

 riphery on the last whorl. The junctions of the axial threads and spiral 

 cords show the merest indication of nodulation. Suture strongly con- 

 stricted. Periphery inflated, strongly rounded. Base rather short, inflated, 

 strongly rounded, broadly openly umbilicated and marked by the feeble 

 continuation of the axial ribs and 16 spiral threads which equal those 

 on the spire in strength. The umbilical wall also shows the feeble con- 

 tinuation of the axial ribs and 13 spiral threads. Here they are a little 

 stronger than on the base. Last whorl solute for about one-tenth of a 

 turn. Aperture broadly ovate; peristome double, the outer flaringly 

 and reflectedly expanded on the outer and basal lip, slightly auriculated 

 at the posterior angle, narrower on the parietal wall and widest at the 

 junction of the inner and basal lip; the inner is slightly exserted, dis- 

 tinct at the posterior angle and on the base, fusing on the parietal wall 

 and outer lip with the outer peristome. Operculum? 



The type (U.S.N.M. No. 504146) I collected on Peterborough Moun- 

 tain, 104 miles north of Port-au-Prince, Haiti. It is a complete specimen 



