284 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 85 



back of the expanded peristome is conspicuously rayed; the inside 

 of the peristome is pale yelloAv. 



The type, U.S.N.M. no. 468809, comes from the Pasada de las 

 Escaleras, Sierra San Andres. It has 6.5 whorls, probably having 

 lost the first half of the nuclear turn, and measures: Length, 27.7 

 mm; greater diameter, 16.2 mm; lesser diameter, 12.4 mm. Addi- 

 tional specimens come from Aserradero, Sierra San Andres. 



This dark-colored race resembles G . tenebrata montalvensis, from 

 which it differs by lacking the orange peristome. 



CHONDROTHYRETES TENEBRATA CANALETENSIS, new subspecies 



Pl.\te 19, Figure 6 



This race comes from the Mogotes del Canalete, south of the 

 Sierra San Andres. 



In this race we have a general marbled and clouded pattern; that 

 is, there are axial bands of brown that in reality are the interrupted 

 sjDiral bands so broadened as to become fused. There is always a 

 pale spiral zone a little posterior to the middle of the base bordered 

 on either side by darker zones. The dark axial band behind tlie 

 peristome is present, and the back of the expanded peristome is con- 

 spicuously rayed, the rays frequently being confluent. The front 

 portion of the peristome, which is pale yellow, is also conspicuously 

 rayed. 



The type, U.S.N.M. no. 468818, has 4.5 turns remaining and meas- 

 ures: Length, 23.5 mm; greater diameter, 15.0 mm; lesser diameter, 

 10.2 mm. 



The clouded marbled pattern of this race will readily distinguish 

 it from all others. 



CHONDROTHYRETES TENEBRATA SCRIPTA, new subspecies 



Plate 19, Figure 2 



This race was collected by Natenson on Mogote Largo, the large 

 second mogote off the southwestern end of the Sierra Guacamayas. 

 It resembles C. tenebrata canaletensis in general color scheme but the 

 spiral bands, which are interruptedly expanded in axial series, are 

 not axially confluent at these widened intervals. The dark rays of 

 the outer lip equal the light intervals in extent. The shells are also 

 larger than in G. tenebrata canaletensis. 



The type, U.S.N.M. no. 468982, has 3.8 whorls remaining and 

 measures: Length, 24.3 mm; greater diameter, 16.8 mm; lesser 

 diameter, 12.5 mm. 



