10 



LAND AND FRESH-WATER SHELLS OF N. A. [PART IL 



tinguished generally by the olive-green epidermis, variegated 

 with purplish-brown patches. I find the number of laminae in 

 the aperture very variable, but the two prominent ones on the 

 labium are constant in all the individuals I have had the oppor- 

 tunity of examining. 



The figure is taken from a specimen received from Mr. Carpenter. 



Fic. 12. 



MfilaMpit.i 

 bkif.niaius. 



Melanipiis bidentatus, Sat. — Shell iraperforate, elliptically- 

 ovate, rather thin, shiniug when perfect, but usually found much eroded ; 

 the surface is marked with longitudinal wrinkles, and very minute re- 

 volving striae; horn-color, or grayish-red, often 

 with revolving, narrow rufous bjinds, four or five 

 in number; suture well marked ; spire short, and 

 usually obtuse, often somewhat eroded ; whirls 

 usually six, the upper ones flattened, the body 

 whirl equalling about | of the entire length of the 

 shell, and obtusely angulated at its greatest width ; 

 aperture hardly oblique, very long and narrow, 

 enlarging gradually towards the base, about f the 

 length of the shell ; peristome very thin and sharp, not reflected, on the 

 interior furnished with no laminae, or with from one to seven ; these 

 laminae are elongated, white, and do not reach the margin ; they are 

 usually separate, placed at irregular intervals, but sometimes are found 

 on a longitudinal elevated, white callus ; they enter but a short distance 

 into the aperture ; the parietal wall of the aperture is covered with a thin, 

 shining, enamel-like callus, and bears on its lower half a single, white, 

 prominent and transverse tooth, entering into the aperture ; the columellar 

 is also furnished with a white, tooth-like fold, commencing at the termi- 

 nation of the sharp peristome, and revolving upwards into the interior of 

 the shell ; this fold does not extend far into the aperture, as all the in- 

 ternal whirls and axis of the shell are early absorbed by the animal. 

 Length of an unusually large individual 13, breadth 7 millimetres. 



Melampus hidentatiis, Say, Journ. Acad. Nat. Sc. Phila. II, 245 (1822) ; 



Binney's ed. 84. — Rcpsell, Journ. Esses Co. Nat. Hist. Soc. I, part 



2, 67 (1839). — Pfeiffer, Mon. Auric. Viv. 45 (excl. Mel. borealis). 



— W. G. BiNNEY, T. M. IV, 156, pi. Ixxv, f. 23. 

 Melampus biplicatus, Pfeiffer, Mon. Aiiric. Viv. 21 ; Br. Mus. 14. 

 Melampus? janmei, Pfeiffer, Mon. Auric. Viv. 25 ; Brit. Mus. Cat. 18. 

 Auricula cornea, Deshayes, Encycl. Meth. II, 90 (1830) ; 1b. in Lam. ed. 



2, VIII, 339 ; ed. 3, III, 390 (1839). 



