THE NATURAL HISTORY SURVEY. 



261 



Length, 16.00; width, 8.50; aperture length, 11.40; width, 6.00 mill. (10440.) 

 " 14.00; " 7.75; " " 9.50; " 5.60 " (10440.) 



Animal: Almost transparent, with a short, wide foot, 

 bluntly rounded behind; head separated from foot by a con- 

 striction, wide, bifurcated; tentacles short, thick, triangular, 

 transparent; eyes black, situated on small prominences at the 

 inner base of the tentacles; color dirty white, darker on the 

 body which is covered with white spots, seen through the 

 transparent shell; edge of mantle transparent, simple; head 

 above lilac-tinted; respiratory orifice on right side of body, 

 near the junction of the upper part of the columella with the 

 body whorl; the head is not much in advance of the edge of 

 the shell when the animal is in motion; the animal appears 

 much too large for the shell. Length of foot 8.00; width 5.50 

 mill. The heart is situated on the left side of the animal, as 

 in desidiosa. The pulsations are rather irregular, three or four 

 being quick, followed by a pause; they vary from fifty-three to 

 sixty per minute. 



FIG. 82. 

 Jaws of LIMN^EA COLUMELLA Say. (Original.) 



Jaw: Three, the median elliptical, smooth, the lateral 

 jaws irregular; finely striated; cutting edges brownish black, 

 shading into yellowish brown as the base of the cartilege is 

 reached (Fig. 82). 



Radula formula: ff+i+f +i+f +i+|M35-' ~35); cen- 

 tral tooth as in the genus; lateral teeth with a quadrate base 

 of attachment; reflection long and rather wide, reaching below 

 the base of attachment, bicuspid, the inner cusp very large and 

 long, the outer cusp small and sharp; the tenth tooth is trifid 

 and connects the lateral and marginal teeth; marginal teeth 

 much longer than wide, generally four-cuspid, the outer cusp, 

 placed about midway of the reflection; the other three placed 

 at the distal end; there are generally several small denticles 



