AMXICOLA. 



85 



Fig. 167. 



Amilicola decisa, Hald. — Aniinal dark colored ; head blackish, get- 

 ting lighter posteriorly ; tentacles translucent, dark on the edges ; an orange- 

 yellow spot at the posterior internal base of the tentacles ; foot yellowish, 

 thickly dotted with black above anteriorly ; anterior edge nearly as dark as 

 the head ; base of the foot thickly dotted with orange on each side of the 

 middle, the dotting being more sparse posteriorly, and entirely wanting 

 anteriorly. 



Shell rather short, conical ; surface smooth, shining (when the dark 

 foreign matter is removed) lines of growth fine ; whirls five, not 

 very convex, sutures impressed, base slightly perforate ; aperture 

 dilated, semicircular, labium slightly concave, in contact with 

 the shell posteriorly, and nearly so throughout its length. 



Color pale-green, and slightly translucent when the black 

 foreign matter is removed. (See Fig. 160, on p. 81.) 



Inhabits small streams connected with the Susquehanna, and 

 has been observed in the Schuylkill by Dr. Griffith. 



Allied to Paludina similis, Mich., of Europe. A greater portion of the 

 labium lies closer to the shell in this species than in any other here de- 

 scribed, except A. nickliniana, and A. tenuipes, which are slender species. 

 At first view it might be taken for a minute Paludina derisa, and I have 

 named it accordingly. In my correspondence I have hitherto called this 

 species limosa. {Haldeman.) 



Amilicola decisa, Haldeman, Mon. p. 7, pi. i, f. 2, 3 (1844?). 



Amnicola 

 decisa. 



8929 

 8944 



No.ofSp. 



Locality. 



From whom received. 



Remarks 



District of Columbia. 



Dr. E. Foreman. 



Cabinet .series. 



Amnicola ciiiciiiuatiensis, Anthony. — Shell Fig. 168. 

 somewhat ventricose, subumbilicate, color delicately green, a 



whirls four, smooth ; spire entire at the apex and promi- (~X 



nent ; suture deeply impressed ; aj^erture much dilated, ^W 



approaching to orbicular, nearly half the length of the Amnionia 

 shell ; length one-fifth of an inch. cincinnatiensis. 



Found in the canal at Cincinnati, clinging to small stones. 

 (^Anthony.) 



Paludina cincinnatiensis, Anthony, Boston J. N. H. Ill, pt. 1 and 2, p. 



279, pi. iii, fig. 3, Jan. 1840.— KiJSTER in Ckeinn. ed. 2, p. 52, pi. x, 



f. 13, 14. 

 Amnicola cincinnatiensis, Anthony, List of Cine. Shells, ed. 2 (1843), 



no descr. — Haldeman, Mon. p. 9, pi. i, f. 4 (1844?). — De Kay, N. Y. 



Moll. 88 (1843). 

 Paludina emarginata, KiJSTEK, Ch. ed. 2, p. 50, pi. x, f. 3, 4. 



" This is the most robust species hitherto noticed among us, 



