AMNICOLA. 7 



Big Sioux River is the only other locality of which I have 

 heard. 



Aiunicola pallida, Hald. — Shell tliin in texture, conical, rather 

 robust, comi^osed of four and a half convex whirls, separated 

 by a well marked suture ; spire obtuse, rather longer than the Yig. 11. 

 aperture ; umbilicus narrow ; aperture ovate-orbicular, forming 

 an angle i^osteriorly ; a small portion of the labium confluent 

 with the body whirl posteriorly. 



Color pale ochraceous, translucent. Amnicnla 



Inhabits Lake Champlain. — Prof. Adams. pallida. 



Intermediate between lustrica and porata. It is not as short 

 and transverse as the former, which, moreover, is widely umbilicate, and 

 has the aperture regularly rounded posteriorly. According to the descrip- 

 tion of Professor Adams, the labium sometimes scarcely touches the body 

 of the shell. The spire is comparatively longer than in porata, the out- 

 line less transverse, and the aperture not orbicular. (Haldeman.) 



Amnicola pallida, Haldeman, Mon. pt. 4, p. 3 and 4 of wrapper ; "Mon. p. 

 12, pi. i, f. 7. 



Amnicola lustrica, Adams, Thompson's Vermont App. p. 2, 19, teste Hal- 

 deman. 



Amilicola lustrica, Sat — Shell conic ; whirls slightly wrinkled, 

 convex ; suture profoundly indented ; aperture oval, nearly orbicular ; 

 labrum with the superior edge not appressed to the preceding whirl, but 

 simply touching it ; umbilicus rather large, rounded. 



Length, less than one-tenth of an inch. Cabinet of the Academy, 



The smallest species I have seen. The aperture somewhat resembles 

 that of a Valvata, to which genus it may probably be referable. Mr. Jes- 

 sup obtained two specimens on the shore of Cayuga Lake. (Say.) 



Paludina lustrica, Sat, Journ. A. N. S. Phila. II, 174 : Binnet's ed, p. 

 69. — KiJsTEE in Chemn. ed. 2, p. 63, pi. xii, f. 6, 7. 



Amnicola lustrica, Haldeman, Mon. p. 16. 



Found also in Wisconsin. 



Amnicola limosa, Sat — Shell conic, subumbilicate, dark horn 

 colored, generally incrusted with a blackish irregular covering 

 on the spire, and sometimes on the body, which completely ob- 

 scures the obsoletely wrinkled epidermis ; aperture ovate-orbi- 

 cular ; suture impressed. 



Length three-twentieths, breadth one-tenth, of an inch. Cabi- 

 net of the Academy. 



Animal whitish ; head brown ; mouth, tentacula, orbits, and 

 vitta on each side of the neck, white ; tentacula filiform, more 

 than half as long as the base of the animal ; rostrum about half as long 

 as the tentacula, annulate with darker lines above ; foot white, brownish 

 above, short, suboval, truncated before, and rounded behind. 



