256 PROCEEDINGS OF THE NATIONAL MUSEUM Vol.89 



tinuation of the axial riblets and by spiral threads equaling those of the 

 spire. The edge of the umbilicus is marked by a strong spiral cord, 

 while the umbilical wall itself is free of spiral sculpture. Aperture 

 almost circular; peristome double, the inner slightly exserted; the outer 

 evenly, moderately broadly expanded and marked by concentric 

 laminae and adnate to the preceding turn at the parietal wall. There 

 is a breathing pore on the parietal wall near the posterior angle of 

 the aperture slightly within the peristome. Operculum typically 

 tudorid . 



The type, U.S.N.M. No. 493425, comes from El Palmarito; that is 

 the north side of El Queque, near Vinales, Pinar del Rio Province. It 

 has almost 3 whorls remaining and measures: Length, 4.5 mm.; 

 greater diameter, 3.0 mm.; lesser diameter, 2.5. mm. 



This species can be readily differentiated from T. {E.) troscheli by 

 having the axial ribs of uniform strength instead of a double series. 



TUDORA (EUTUDOREX) TROSCHELI (Pfeiffer) 



Shell small, thin, semitranslucent, pale straw yellow. Nuclear 

 whorls 1.5, forming a blunt apex, well rounded, microscopically 

 granulose, with the last portion of the last turn showing the beginning 

 of the postnuclear sculpture. Postnuclear whorls inflated, well 

 rounded, marked by retractively slanting axial riblets, which are not 

 all of the same strength, but several slightly weaker ones are separated 

 by a little stronger element. These riblets, particularly the stronger 

 ones, become slightly expanded into small auricles at the summit. 

 The spiral sculpture consists of very slender threads, which cross the 

 intercostal spaces but not the ribs. These threads differ in strength 

 and spacing in the different subspecies. Suture strongly constricted. 

 Periphery inflated, stronglj'' rounded. Base short, inflated, strongly 

 rounded, openly umbilicated, marked by the continuation of the axial 

 ribs, which here become much intensified, the stronger elements 

 becoming decidedly lamellose; the fine spiral sculpture described for 

 the spire is also present on the base; in addition to that, two con- 

 siderably stronger spiral threads mark the outer limit of the umbilicus. 

 The umbilical wall is marked by the continuation of the axial riblets. 

 Aperture almost circular; peristome double, the inner slightly exserted; 

 the outer rather broadly expanded and slightly reflected, marked by 

 concentric laminae adnate to the preceding turn on the parietal wall. 

 Operculum typically tudorid. 



This species is confined to Pinar del Rio Province, where it appears to 

 range from Pan de Azucar through Cayos de San Felipe and Viiiales 

 to the mogotes south of the Sierra de San Andres. 



We are recognizing four subspecies, which the following key and 

 descriptions will help to differentiate: 



