266 THE CHICAGO ACADEMY OF SCIENCES. 



inflated; color light or dark horn; surface shining, covered 

 with numerous crowded, fine lines of growth, which can 

 scarcely be discerned on the apex; whorls five, somewhat 

 shouldered in some forms, the shoulder being near the suture; 

 the last whorl is very large, half the length of the entire shell; 

 each whorl is double the size of the one preceding; spire 

 sharply-conical; sutures very deeply indented; aperture elon- 

 gately ovate, somewhat expanded; peristome thin, acute; col- 

 umella thickened by a testaceous deposit, and bearing a heavy 

 plait across the middle; the columella is reflected at the lower 

 end, the reflection almost covering the umbilicus, which is 

 narrowly open; the umbilical region is somewhat indented. 

 The surface is sometimes broken up by coarse, spiral semi- 

 ridges into facets, forming a somewhat reticulated surface. 



Length, 12.00; width, 6.00; aperture length, 6.00; width, 3.00 mill. (8457.) 



12.00; " 5.25; " " 6.00; " 3.50 " (8457.) 



10.00; " 4.00; " " 5.50; " 2.50 " (8457.) 



8.75; " 5.00; " " 4.50; " 2.50 " (8457.) 



13.00; " 5.75; " " 7.50; " 4X)0 " (8468.) 



Animal (Fig. 84): With a very small, more or less oblong 

 foot, when viewed from the base, the anterior and posterior 

 borders rounded; color dark gray or blackish, lighter below; 



FIG. 84. 

 Animal of LIMN^EA DESIDIOSA Say. (Binney, Fig. 25.) 



the whole surface is dotted with whitish, which- is specially 

 noticeable about the eyes; tentacles triangular, flat, short, more 

 or less transparent; the black eyes are placed on prominences 

 at the inner base of the tentacles; respiratory orifice on the 

 right side, near the angle of the peristome and body whorl. 

 Length of foot 5.00, width 3.00 mill. The heart is situated near 

 the umbilicus and the pulsations are very rapid; the writer 

 counted one hundred and fifty to one hundred and fifty-five 

 per minute. 



Jaw: As usual. 



Radula formula: f +!++ };+-H-f+f (46-1-46); cen- 

 tral tooth as usual; lateral teeth! with a subquadrate base of 

 attachment, the reflection very broad, bicuspid, the inner cusp 



