UROCOPTIS, S. G. GONGYLOSTOMA. 267 



sparingly variegated with a paler tint. Spire noticeably 

 tapering above, truncate, the suture subcrenulate. Whorls 

 remaining 14-15, flattened, the last adnate, with a thread- 

 like basal keel. Aperture subcircular, the peristome equally 

 expanded throughout, white. Internal column encircled by 

 a single acute, oblique lamina. Length 14-16, diam 3 mm. 

 (Arango). 



Central Cuba : San Juan de las Lleras, near Villaclara. 



C. contentiosa ARANGO, Proc. A. N. S. Phila. 1884, p. 211 

 (Nov. 4, 1884). 



The position of this species in the series is uncertain. 



Section Tetrentodon Pilsbry, 1903. 



Trackelia PFR. (in part), Monogr. Helic. Viv., iii, p. 564 

 (1853), proposed for marmorata Shutt., volubilis Morel., 

 porrecta Gld., gracillima Poey, speluncce Pfr., subtilis, Morel., 

 gouldiana Pfr., rugeli Shutt., riisei Pfr., cinerea Pfr., morini 

 Morel., philippiana Pfr., scalarina Shutt. Name preoccupied 

 by Scopoli in Aves, 1777, by Serv. in Coleoptera, 1834, and 

 by Westwood in Coleoptera, 1839. 



Shell attenuate, entire or shortly truncate, the neck cylin- 

 dric, rounded beneath; axis very weakly one- or two-plicate, 

 the spirals not crenulate; apex swollen, smooth. Radula 

 narrow, with 13 to 19 teeth in a transverse row, the inner 

 two laterals on each side much larger than the succeeding 

 teeth. Type U. plicata (Poey). 



A group of slender-shelled Cylindrellas, found in the prov- 

 inces of Matanzas and Havana, with a single species in New 

 Providence, Bahamas. The series is related on one hand to 

 Cochlodinella, from which it differs in the more or less pli- 

 cate axis, and on the other to the very slender forms of 

 Tomelasmus, of the group of U. wrigliti, in which, however, 

 the axis has a spinose lamella in the upper whorls. 



The species of Tetrentodon were referred to the genus 

 Brachypodella in my paper of 1898, but having examined 

 the teeth of most of them, I find that the affinities of the 

 group are wholly with the west Cuban forms of Urocoptis. 

 The dentition (pi. 43, fig. 3, U. cyclostoma; fig. 4, U. plicata; 



