EXPLORATION OF ALASKA. 245 
plates. The diverticle of the cesophagus nearly as large as the true 
bulbus. The spermatoduct and the penis as usual, also the vagina ; 
the spermatotheca of 1.6 mm. largest diameter. No trace of pig- 
ment on the vagina or penis, and the peritoneum was colorless. 
Another variety of the species, with “brown mantle and yellowish- 
white papillae,” was dredged by Dall, in Yukon Harbor (Shumagins), 
in August, 1874, on sand and stones, at a depth of six to twenty 
fathoms. 
The individual preserved in spirits was 9.0 mm. long, by a breadth 
of 6.5 mm., and a height of 4.5 mm.; the breadth of the foot 4.0 mm., 
the height of the gill 1.5mm. The back of the animal densely brown- 
dotted, especially the circumference of the gill and the free area left 
in the middle of the gill; the dorsal papille all whitish; the stalk of 
the rhinophoria and the inferior part of the club densely dotted with 
brown, also, in a somewhat slighter degree, the outside of the branchial 
leaves. The under side of the mantle and the upper side of the margin 
of the foot and, in a slighter degree, the sides of the body and the sole 
of the foot dotted with an enormous quantity of brownish-gray points. 
The form as usual, The gill with nine leaves, of which the two pos- 
terior were much smaller than the others. 
The central nervous system as usual; the otocysts very conspicuous 
under the magnifier as chalk-white points. The mouth-tube 2.0 mm. 
long. The bulbus pharyngeus 2.0 mm. long; the sheath of the radula 
projecting 2.0 mm., bent downwards. The armature of the lip-disk 
(Pl. XII, fig. 10, 11) very like that of the var. ulbescens (ef. Pl. XIII, 
fig. 4). ‘Che buccal crop as usual. The tongue with nine rows of 
plates; the total number of rows, twenty-five (13+3). The large 
lateral plates as usual; the denticulations rather long and somewhat 
irregular. ‘The number of the external plates (fig. 12) reaching to six: 
The salivary glands, the cesophagus with its diverticle, the pyloric 
part of the intestine with its bag (biliary sac), and the liver, as usual. 
The sanguineous gland rather large, covering, besides the central 
nervous system, the whole of the bulbus pharyngeus. 
In the lobes of the hermaphroditic gland, masses of zojsperms. The 
anterior genital mass of the usual form; the ampulla of the herma- 
phroditic duct somewhat larger. ‘The spermatoduct as usual; so, too, 
the penis, with its armature; the length of the glans about 0.5 mm. 
The spermatotheca and the spermatocysta as usual; also the chief 
duct (vagina), the cavity of the last filled with sperma. The mucous 
gland yellowish-white and in the centre (albuminous gland) brownish- 
