220 UROCOPTIS, S. G. GONGYLOSTOMA. 



Cylindrella elegans PFR., 1. c., 1840, i, p. 42 ; Phil., Abbilcl, i, 

 p. 180, pi. 1, f. 12; Monogr., ii, p. 374; iii, 572; iv, 701; vi, 

 371; viii, 434; Conchyl. Cab., p. 23, pi. 3, f. 3-5 (typical; 

 6-11 var.). DESK., in Fer., Hist, p. 228, pi. 164, f. 26-28. 

 A. SCHMIDT, Der Geschlechtsapparat der Stylommatophoren 

 in taxonomischer Hinsicht, Abh. Nat. Yer. Sachsen u. Thur. 

 in Halle, p. 50, pi. 14, f. 110 ( genitalia) . W. G. BJNNEY, 

 Proc. A. N. S. Phila. 1875, p. 251, pi. 20, f. 6, and Ann. N. Y. 

 Acad. Sci., iii, p. 126, pi. 14, f. B (dentition). ARANGO, 

 Contrib., p. 113. Pupa elegans Pfr., GLD., Bost. Journ. N. H., 

 iv, p. 490. Pupa (Siphonostoma) lituus GLD., Bost. Journ., 

 iv, pt. 1, on cover. Cyl. nobilis STENTZ mss., teste Villa. 

 Pupa obtorta MKE., in litt., teste Pfr. Balea truncatula 

 VILLA Disposit. Syst, p. 25, teste Pfr. ; no descr. (1841). 



The typical form of U. elegans (pi. 53, figs. 41-45, 66) is 

 a long, pillar-shaped, ivhitish-corneous shell, with the strongly 

 tapering upper third or fourth of the length of a broiun or 

 reddish tint, or sometimes pale yellowish. It is often a little 

 wider at the upper third, or the lower two-thirds may be 

 cylindrical. The truncation is narrow. The Avhorls are dis- 

 tinctly convex, numerous, 13 to 17 in normal truncate speci- 

 mens, and 22 to 24 in those retaining the apex in maturity, 

 according to Pfeiffer, who found several. The last whorl 

 becomes free, tangential and slightly descending, and is usu- 

 ally a little flattened at the top of the neck. The stride are 

 arcuate and regular, slightly narrower and sharper on the 

 neck. The longest axis of the aperture is obliquely trans- 

 verse ; it is slightly ovate, the columellar side being less arcu- 

 ate and wider. The axis bears two spiral lamellae, both 

 becoming obsolete in the last whorl, about equal in the pi 

 ceding two whorls, while in several still earlier whorls the 

 upper lamella predominates, and there may be a weak median 

 cord developed. The lower lamella is finely more or less 

 denticulate, and in one or two median whorls it usually is 

 shallowly grooved along the summit, with a narrow denticu- 

 late thread in the furrow. 



Length 19.5, diam. 3.6 mm. ; whorls 17 1 /2 (but plug at 

 whorls) . 



