1880.] NATURAL SCIENCES OF PHILADELPHIA. 65 



a little larger than the bulbus. The radula brownish-yellow, with 

 nine rows of teeth, further back fifteen developed and two younger 

 rows, the total number being twenty-six. The teeth quite as above, 

 dark, horn-colored in their thicker parts ; the median ones reaching a 

 height of 0.16 mm. The salivary glands as above-mentioned. 



The biliary sac uncommonly small. The black contents of the 

 rectum consisting of undeterminable animal matter, mixed with larger 

 and smaller pieces of small Crustacea. The liver much flattened on 

 the riglit anterior half. 



The anterior genital mass large, about 7.0 mm. long, 5.0 mm. high, 

 and 3.0 mm. thick. The ampulla of the hermaphroditic duct whitish, 

 forming a long ansa, about 5.0 mm. long. The spermatoduct shorter 

 than in the other form, otherwise, with the penis, as in that form. 

 The spermatotheca yellowish, short, sac-shaped, of a largest diameter 

 of 3.0 mm. ; the spermatocysts about 0.3 mm. long, pyriform. The 

 mucous gland chalk-white and brownish-gray. 



Of another variety, Dall, in August, 1872, obtained six specimens, 

 in Sanborn Harbor (Shumagin Ids.), on stony bottom, at low water. 



According to Dall, the color of the back of the living animal is 

 " red-brown, with whitish papilla3." The color of the backs of 

 the specimens preserved in spirits was rather uniformly, dirty brown- 

 yellowish, commonly much lighter on the middle, the papilliB whitish ; 

 the gill and the rhinophoria of the color of the back ; the under side 

 of the whole body yellowish ; more whitish on the mantle. The 

 length of the animals varied from 18.0 to 25.0 mm., by a breadth of 

 11.0 to 16.0 mm., and a height of 8.0 to 12 mm. ; the breadth of 

 the foot '1.5 to 12.0 mm. ; the height of the rhinophoria reaching 3.0 

 mm., that of the gill 2.0 mm. The form as usual. The horseshoe 

 shape of the gill very pronounced, the number of leaves, twenty-eight 

 to thirty. The gill was surrounded by higher papillae, which, in the 

 largest specimen, reached the height of about 2.5 mm. ; the space 

 inclosed by the gill closely set with similar papillas, the largest (as 

 large as the above mentioned) in the periphery. The gill can be so 

 deeply drawn back in its groove, that these external and internal 

 papillai shut over and quite conceal it ; the papilla? of the centre 

 smaller ; a crest or some few papilhe in the median line go from the 

 anus backwards, between the incurved ends of the gill. The anus 

 small, very slightly prominent ; the renal pore on the right side. The 

 openings of the rhinophor-holes as usual, before them the two usual 

 papilUc, behind them a bare space. The papilla? of the back quite as 



