54 LAXD AND FRESH-WATER SHELLS OF N. A. [PART IV. 



Observations. — This species is closely allied to T. undulatnm, Say, 

 but may at once be distinguished by its lower spire and proportion- 

 ately wider base, where it is flatter. The undulations on Mr. Say's 

 shell are low, while in Lesleyi these are replaced by well defined 

 tubercles, which are disposed to be compressed and incline to the 

 left. There is only a single row of these tubercles, but those of the 

 row above cause swellings on the upper part of the whorls. In 

 the young state they differ totally, the undulatnm be- 

 Fig. 104. jyg entirely smooth, while the Lesleyi has tubercles 



to the apex, except that on the first two or three 

 whorls tliey change into folds. In the multiplicity 

 of nodules it resembles Lithasia pernodosa (nobis). 

 In the spire it also resembles L. armigera, Say, and 

 L. Jayana (nobis), but difl'ers in the aperture being 

 Trypanostomose and of course not belonging to the 

 same genus. I have ten specimens before me. 

 Those from Prof. Troost I have had for a long time 

 and believed they might be a variety only of undulatmn, but the 

 young sent by Mr. Lesley and Major Lyon convinced me at once that 

 the species was new and distinct. The aperture is more square than 

 in undulatum and the fuse is less. The young are striate on the 

 under part of the whorls, which is never the case with undulatnm. 

 The aperture is about one-third the length of the shell. I have great 

 pleasure in naming this after Mr. Joseph Lesley, Civil Engineer, to 

 whose kindness I am indebted for many Kentucl^y species. — Lea. 



A second specimen, kindly furnished by Mr. Lea, is more 

 elongated than his type. The species bears the same relation 

 to undulatum that Jilum does to canal iculatum ; and it is strik- 

 ingly like Say's armigera. 



3. P. undulatum. Say. 



Melania undulata, Say. New Harmony Dissem., p. 261 ^ Reprint, p. 17; Bixnet'S 

 edit., p. 14i. Reeve, Monog., f. 307. Haldejian, Am. Jour. Sci., xlii., p. 

 •210, Dec, 1841. Anthony's List, l.st and 2d edits. DeKay, Moll. N. Y., p. 92. 

 WiiEATLEY, Cat. Shells U. S., p. 27. Jay, Cat., 4th edit., 275. Binney, Check 

 List, No. 281. BuoT, List, p. 31. Hanley, Conch. Misc., t. 1, f. 10. Catlow, 

 Conch. Nomenc, p. 18f». Brot, Mai. Blatt., ii, p. lOG, July, 1800. 



Megara undulata, Say, Chenu, Man. Conchyl., i, f. 2025. Adams, Genera, i, p, 306. 



Description.— Shell large, elevated, conic, brownish, with a broad, 



