AMNICOLA. 3 



concurs witli rae in instituting the genus Amnicola. Its position 

 seems to be intermediate between Paludina and Melania. 



Under this genus will come P. 2)orata, lustrica, grana, and 

 limosa of Say ; nickliniana of Lea ; and cincinnatiensis of 

 Anthony, and perhaps some of the sub-globular llelanise. 



The genus Nematura of Benson includes shells very similar to 

 these, but they are said to have the last whorl contracted, as it 

 approaches the aperture. (Gould.) 



The figures which I have given are all somewhat enlarged. 



I have grouped the species into two sections : — 



§ 1. Shell elongate. § 2. Shell globose. 



§ 1. Elongate. 



Amnicola attenuata, Hald. — Shell unusually long, slender, with 

 6 or 7 obliquely revolving, very convex -whirls, separated by a deep 

 suture ; aperture small, ovate, with the peritreme level and 

 continuous ; labium in contact with the body whirl, leaving Yis. 3. 

 scarcely any perforation. 



Color pale-green beneath an extraneous coating of black. q 



Taken from a spring in Montgomery County, Virginia, r~) 



connected with Roanoke River. ^^ 



I am not confident that this is not the adult of Nickliniana, Amnicola 

 as there is a very close resemblance between that shell and attenuata. 

 the young of this species, when it has but four volutions. 

 In the latter, the aperture appears to be rather contracted. (^Haldeman.) 



Amnicola attenuata, Haldeman, Mon. pt. 4, p. 3 of wrapper — Ih. Mon. p. 

 22, pi. 1, f. 22-/6. Journ. Acad. N. Sc. Phila. VIII, p. 200-/6. 

 Proc. I, 78. 



Amnicola elongata, Haldeman, 1. c. in plate. 



It is also said to inhabit New York. Amnicola elongata, Jay 

 of the Smithsonian Check Lists is probably this species. No 

 synonymy or reference is given by Dr. Jay (Cat., p. 278). 



Amnicola lapidaria, Say — Shell turreted, sub-umbilicate, with 

 six volutions, which are obsoletely wrinkled across. Suture 



impressed. Aperture longitudinally ovate-orbicular, opercu- -p. . 

 lated, rather more than one-third of the length of the shell. 



Length about one-fifth of an inch. Collection of the Aca- A 



demy of Natural Sciences. rj^ 



Inhabitant not so long as the shell, pale ; head elongated xJ 



into a rostrum as long as the tentacula, and emarginate at Amnieola 



tip ; tentacula two, filiform, acuminated at tip, short ; eyes lapidaria. 



