20 



THE NAUTILUS. 



bordered by a porcelain-white line which is rarely edged with chest- 

 nut ; aperture rather long, long-oval in form, much narrowed at the 

 upper part, more than a half and less than two-thirds the length of 



Fig. 3. 



the entire shell ; peristome thin, thickened within 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 hiber- 

 nation 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-colored whorl. 



Length 17.00; width 9.00; aperture length 11.00; width 4.50 

 mill. (Chicago.) 



Length 26.00; width 12.00; aperture length 14.00; width 5.50 

 mill. (Chicago.) 



Length 24.00; width 11.50; aperture length 13.00 ; width 5.50 

 mill. (Chicago.) 



Length 19.00; width 10.00; aperture length 12.00; width 5.00 

 mill. (Chicago.) 



Length 22.00 ; width 10.00; aperture length 12.50; width 5.00 

 mill. (Chicago.) 



Animal with a long and rather narrow foot, acutely pointed be- 

 hind and rounded before, Avhere it is produced into lateral lobes ; 

 the foot does not extend much beyond the edge of the shell ; color 

 blackish or yellowish gray, dotted or flecked with whitish or yellow- 

 ish, the dots being distinctly seen through the transparent shell ; the 

 front of the head is ornamented by 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 produced into four filiform digitations ; tentacles very 

 long and slender, tapering to a point ; head distinct, separated from 



