II 



60 new-york fauna — mollusca. 



Planorbis bicarinatus. 



PLATE IV. FIG. 63. A. ». 



(STATE COLLECTION.) 



Planorbit bicarinatus. Say, Nich. Encyclop. Vol. 4, No. 2, pi. I, fig. 4. 



P, id. Id. American Conchology, pi. 54, fig. 3. 



/- U. Hai.dk.man, Limniadas, p. 3, pi. 1, fig. 1. 



/>. id. Gould, Invertebrata of Mass. p. 203, fig. 134. 



Description. Shell orbicular, deeply indented above and beneath. Whorls three, wrinkled 

 with minute revolving lines, and strongly carinate on both its sides. Aperture large, abruptly 

 vaulted at the carina of the right or upper side. Lip slightly expanded. 



Color. Pale yellow or brownish ; reddish brown within, lighter colored on the carina 

 Animal brownish, dotted with light reddish yellow. Foot tongue-shaped. 



Diameter of the shell, 0'5. Height 0'3. 



Not as numerous as the preceding, but found in sluggish streams and ponds in the State 

 The figure is not at all characteristic of the species. 



Planorbis lentus. 



PLATE V. FIG. 80.* a. b. 



(STATE COLLECTION.) 



Planorbis lentus: Say, Am. Conchology, pi. 54, fig. 1. 



P: tcli Gould, Invertebrata of Mass. p. 202, fig: 132 



Description. Whorls three above and four beneath, marked by raised incremental lines 

 above, or on the right side, concave, with a distinct suture ; beneath, not so deep : the whorls 

 slightly carinate. Aperture large, oval ; its lower margin lying in the plane of the transverse 

 diameter of the shell. 



Color. Dark greenish ; lip within dark reddish brown. Animal, dark olivaceous above 

 and below : foot oval, minutely dotted with yellowish. 



Size of the preceding. 



This is nearly as common as the preceding, with which it has usually been confounded. 

 It is chiefly distinguished from it by the left margin of the lip being in the plane of the trans- 

 verse diameter, whilst in trivolvis it is below it. 



