COELOCENTRUM. 41 



C. FISTULARE (Morelet) . PI. 9, figs. 16, 17, 18, 19, 20. 



Shell narrowly rimate, cylindric-turreted, rather thin, sub- 

 diaphanous, very densely arcuate-striate, but little shining, 

 gray-whitish. Spire attenuated above, rather widely trun- 

 cate; suture impressed, lightly submarginate-crenate, whorls 

 remaining 11 to 12, subequal, slightly convex, the last scarcely 

 receding under the penultimate, free in front, shortly pro- 

 tracted, compressed-carinate above and at the base, thread- 

 keeled a little below the middle. Aperture oblique, irregu- 

 larly subtetragonal-oval, dull whitish inside ; peristome con- 

 tinuous, narrowly expanded and a little reflexed throughout, 

 whitish ; left margin forming an angle with the horizontal pa- 

 rietal and with the basal margins, outer margin very much 

 arched. Foramen of the truncate spire rather wide, slightly 

 perspective. Length 28, diam. 8 mm. Aperture 5 mm. long, 

 5 wide. (C.&F.). 



Northern Guatemala: forests of Peten (Morelet) ; Vera Paz 

 (Salvin) ; Coban (Sarg). 



Cylindrella fistulans MORELET, Test. Noviss. i, p. 10, 110. 12. 

 -PFR., Monogr. iii, p. 569 ; Conchyl. Cab., p. 38, pi. 4, f . 21, 

 22.C<rlocentrum fistulare Fisch. & Crosse, Moll. Mex. i, p. 

 343, pi. 15, f . 12, 12 a. STREBEL, Beitrag iv, p. 58, pi. 6, f . 2 ; 

 pi. 14, f. 1 A, B. MARTENS, Biologia, p. 272. Cylindrella arc- 

 tispira TRISTRAM, P. Z. S. 1863, p. 412 (not of Pfr.). 



Very near C. tomacella, but differing in the gray-whitish 

 color, more lustreless shell, usually smaller size, slightly less 

 swollen shape, and subtetragonal rather than subtriangular 

 aperture. It has fewer whorls, slightly less fine striation, and 

 finally a narrower umbilical fissure. These differences, found 

 by Crosse and Fischer on comparing the types of both species, 

 are rather elusive, and in actual practice probably of little 

 value. Probably C. fistulare should be subordinated to toma- 

 cella as a mere race or variety. Strebel, who examined speci- 

 mens brought by Sarg from Coban, states that the sculpture 

 scarcely differs from that of tomacella. The whorls are very 

 feebly convex. The internal column is strongly swollen, with 

 fine and serrate lamellffi in the upper whorls, later increasingly 

 stronger, so that in the middle whorls the serrations are almost 



