312 THE CHICAGO ACADEMY OF SCIENCES. 
upper part, more than a half and less than two-thirds the length 
the entire shell; peristome thin, thickened on the inside by a 
callus which is either bordered by a dark chestnut band or else 
is itself of that color; columella thickened with a decided 
white callus or plait; the lower part of the aperture is produced; 
the periods of winter hibernation are frequently marked by a 
whitish band in the body of the shell; protoconch consisting 
of a trifle more than one smooth, rounded, dark chestnut-col- 
ored whorls. 
Length, 17.00; width, 9.00; aperture length, 11.00; width, 4.50 mill. -(9331.) 
eel 68! Umea rey bs es ': 14,00; « 5.50 “ (8493.) 
SS) D002 « PS ETDs sg - 13.00; “ 5.00 “  (8498.) 
$e 1900s “18,00; s “ 12.00; « 5.00 “ (8493.) 
Me eee UO hy OOD: < r 12.50; "BOR" 8 (BETES 
Animal: Witha long, rather narrow foot, acutely pointed 
behind and rounded before, where it is produced into two lateral 
Fie. 110, 
Animal of PHysA GYRINA Say. (Original.) 
lobes (vela); the foot does not extend much beyond the edge 
of the shell, color blackish or yellowish gray, dotted or flecked 
with whitish or yellowish, the dots being distinctly seen through 
the transparent shell; the front of the head is ornamented 
with two yellowish spots of good size, composed of numerous 
minute dots; the mantle is brown, spotted with yellowish, is 
reflected over a portion of the shell on the right side and pro- 
duced into 4-10 filiform digitations arranged in two series 
apical and columella; tentacles very long and slender, taper, 
ing to a point; head distinct, separated from the foot by a 
short neck; mouth large, in the lower plane of the head, show- 
ing plainly the jaw and radula while the animal is grazing 
along the side of an aquarium; eyes placed on swellings at the 
inner base of the tentacles; respiratory cavity on left side of 
shell at the lower point where the peristome meets the body 
whorl, Length of foot, 15.00 mill.; width, 4.00 mill. (Fig. 110). 
Jaw: In one piece, arched, striated, provided with a cen- 
