UROCOPTIS, S. G. GONGYLOSTOMA. 203 



a 1 . Lower lamella slender in the last whorl. 



b. Truncate, with 12 whorls, length 11-13 

 mm. 7. oligomesus, no. 79. 



c. Entire or narrowly truncate ; whorls 16 in 

 truncate, 19-23 in entire shells ; length 13- 

 16 mm. 



U. saxosa, no. 77 ; U. patruelis, no. 78. 



d. Entire or narrowly truncate; whorls 18- 

 20 in entire shells; length 11-13 mm. 



U. notata, no. 76. 



U. c&cilia, no. 75, described as similar to elegans but with 

 Pour lamellae, may belong to this group, or to the typical 

 group of Gongylostoma. 



71. U. GUIRENSIS ('Gundl.' Pfr.). PI. 48, figs. 9, 10, 16. 

 Shell cylindrical, the upper third or fourth rather rapidly 



tapering to a narrow truncation; thin, corneous or whitish- 

 corneous, lustreless, regularly sculptured with narrow white 

 riblets, which are arcuate or nearly straight, but slightly 

 oblique, and separated by intervals about three times the 

 width of the riblets. Whorls slightly convex, the last rounded 

 and very weakly, obtusely keeled below, shortly free in front. 

 Aperture subcircular, the peristome narrowly reflexed. Axis 

 with three lamellae, all continuing into the last whorl, sub- 

 equal in the penult, whorl, but in the median whorls the upper 

 one is much the largest, and the lower smallest (fig. 16). 



Length 16.5, diam. 2.6 mm.; whorls 15 (spire truncate). 



Length 17.5, diam. 3 mm.; whorls 20 (Pfr.; spire entire). 



Western Cuba : Sierra de Guira, dist. Santiago de los Banos, 

 Pinar del Rio, on moss-covered stones in shady places (Gund- 

 lach). 



Cyl. guirensis Gundlach mss., PFR., Malak. BL, xi, 1863, 

 p. 11, no. 60; Monogr., vi, p. 379. ARANGO, Contrib., p. 120. 



Well distinguished by the thread-like riblets and the dis- 

 parity in size of the lamellae in the median whorls, as shown 

 in the upper part of fig. 16. 



72. U. STEARNSI (Gundlach). 



Shell shortly rimate, cylihdric-turrete, truncate, obliquely 



