312 PROCEEDINGS OF THE NATIONAL. MUSEUM vol. 85 



This is the large race that is extremely abundant on the cliffs of 

 the middle ground bordering the path to Kangel. We gathered 

 hundreds of specimens as we made our way to the old Cafetal at the 

 summit. These show varying degrees of umbilication. The sculp- 

 ture is much stronger than in the other subspecies here recognized, 

 for the junction of the axial ribs and spiral threads produces sharp 

 cusps. 



The specimen figured, U.S.N.M. no. 492733, is a complete individ- 

 ual having 6.0 whorls and measuring: Length, 16.7 mm; greater 

 diameter, 13.2 mm; lesser diameter, 9.6 mm. 



CHONDROTHYRELLA (PLICATHYRELLA) CLAUDICANS CULMINIS, new subspecies 



Plate 27, Figuee 2 



On the summit of Rangel we found on isolated limestone blocks, 

 among the coffee plantation, many specimens that were quite uni- 

 formly smaller, somewhat paler, and with more closely crowded and 

 weaker axial riblets, which do not form cusps at their junction with 

 the spiral threads but small nodules. To these we are applying the 

 above name. 



The type, U.S.N.M. no. 492734, has 4.5 whorls remaining and meas- 

 ures: Length, 12.3 mm; greater diameter, 9.8 mm; lesser diameter, 

 7.1 mm. 



Similar shells were collected by Hermano Roberto at the Cueva 

 del Rosario, east of and across the river Santa Cruz from Rangel. 



CHONDROTHYRELLA (PLICATHYRELLA) TENEBROSA (Morelet) 



Shell small, very broadly ovate, chestnut-brown, with faint darker 

 interrupted spiral bands of brown ; the peristome may also be chest- 

 nut-brown or pale yellow or between these two colors. The nuclear 

 whorls are lost in all our specimens. The postnuclear whorls are very 

 much inflated, rotund, and crossed by slightly sublamellar, retrac- 

 tively curved, axial riblets, which are distantly spaced on the early 

 turns and quite closely approximated on the last whorl, passing un- 

 diminished over the inflated periphery and base of the last whorl into 

 the umbilicus. The spiral sculpture consists of slender threads that 

 render the axial riblets somewhat wavy and slightly nodulose at their 

 junction. On the anterior half of the base and in the umbilicus the 

 spiral threads become stronger and more distantly spaced, forming 

 here decided cusps at their junction with the axial riblets. Aperture 

 very broadly ovate, almost circular, peristome double, the outer 

 very broadly expanded, radially fluted and marked with concentric 

 lines of growth, two to three times as wide posterior to the fold on the 

 inner lip as on the rest of the aperture. The plication on the inner 

 lip is usually not strong. Inner peristome slightly exserted and re- 



