64 LAND AND FRESH--\VATER SHELLS OF N. A. [PART U. 



Limnsea parva is placed doubtfully, by Ilaldeman, iu the 

 synonymy of L. humilis. I have so placed it after au examina- 

 tion of the description and the type which is drawn iu Fig. 102. 



Mr. Lea also quotes L. exigua from San Antonio AiToya. No. 

 8523 of the collection, from the Yellowstone River, i;^ labelled 

 L. curta, by Mr. Lea. These and the other species of the same 

 author, given in the synonymy, are all drawn below, the figures 

 being in each case from the original specimeu. The original de- 

 scriptions, also, are given. 



Of L. linsleyi, also, I give the original description and a fac- 

 simile of the original figure. 



Limnsea modicella, Say. — Shell blackish, not elongated ; whirls rather 

 more than four, convex ; suture deeply impressed ; apex acute ; 

 100. aperture very regular, the labium and labrum being sub-equally 

 curved ; the fold of the columella rather slight. Total length 

 seven-twentieths of au iuch, breadth one-fifth ; length of the 

 aperture one-fiftli. 



Smaller than any of the species I have hitherto described. It 

 modicella. '^^^ found, by Dr. M'Eueu, at Oswego, on the Susquehanna River, 

 near the State of New York. (Sai/.) 



Limnaea curta. — Shell subturreted, rather thin, shining, subdiaphanous, 

 yellow, perforate ; spire elevated ; sutures impressed ; whirls six, convex ; 



aperture small, elliptical. 

 Fig. 101. jj^f^^ Cincinnati, Ohio : T. G. Lea. Poland, Ohio: Dr. Kirt- 

 ^\ land. My cabinet, and cabinets of T. G. Lea and Dr. Kirtland. 

 \ffj Diam. .18, length .32 of an iuch. 



A very small, erect species, resembling, in the form of the aper- 

 . ture, a Butimus, the fold being scarcely perceptible. In its 



general outline it resembles a Paludina more tlian most Limnsea'. 

 In these characters it is allied to L. bulimoides herein described. The 

 aperture is rather more than one-third the length of the shell, and the last 

 whirl is wrinkled. The columella is thickened, aud rellected over the 

 perforation. {Lea.) 



Limnsea parva. — Sliell subturreted, thin, smooth, diaphanous, horn color, 

 subperforate ; spire elevated; sutures impressed; whirls five, 

 °* ~" convex; aperture elliptical. 



Ilab. Cincinnati, Ohio: T. G. Lea. My cabinet, and cabinet 

 of T. G. Lea. Diam. .12, length .22 of an inch. 



This is the smallest species %vhich has come under my notice. 

 In general form it resembles L. curta, herein described. It is 

 rather less inflated, has a longer aperture, and is diminutive. 



