EXPLORATION OF ALASKA. 191 
with about thirty leaves (on each side). The back all over minutely 
and densely villous (fig.3). The margin of the rather wide (5.0 mm.), 
roundish branchial aperture like the margin of the rhinophor-holes, 
prominent, finely crenulate; the branchial leaves (retracted) six in 
number, very strong, tri- or quadripinnate. The anus strong, about 1.5 
mm. high, cylindrical, closing the branchial ring posteriorly ; the renal 
pore as usual. The edge of the mantle rather thick, projecting about 
2.0 mm. from the body; the sides low. ‘The genital opening as 
usual, with two distinct apertures at the bottom. The foot strong, 
broad, somewhat narrower towards both ends; in the anterior margin 
a strong furrow, towards the median line deeper and forming two lips; 
the superior broader and divided in the median line. 
The cerebro-visceral ganglia kidney-shaped, the visceral larger than 
the cerebral; the pedal of roundish contour, scarcely larger than the 
visceral. The buccal ganglia of oval form, connected by a short 
commissure; the gastro-cesophageal roundish, short-stalked, in size 
about one-fifth of the former, with one very large and one large cell. 
The eyes short-stalked, with black pigment and yellowish lens. The 
otocysts scarcely smaller than the eyes, overcrowded with otokonia of 
the usual kind. The leaves of the rhinophoria strengthened with long, 
perpendicular spicula, calcified at the surface. The tentacula with a 
mass of shorter, but otherwise similar spicules, lying irregularly. 
The villi of the back closely set with perpendicular spicula (tig. 3). 
The anal papilla with long, perpendicular spicules; the stalk of the 
branchial leaves with many shorter spicula, irregularly situated; in the 
leaves themselves were no spicules. In the interstitial connective 
tissue large spicules were seen rather sparsely. 
The oral tube was about 1.5 mm. long, wide, with strong longitudi- 
nal folds. The bulbus pharyngeus only about 4.0 mm. long, by a 
height of 2.0 mm., and a breadth of 4.0 mm.; the rasp-sheath very 
_ prominent on the hinder part of the under side of the bulbus; the 
inner mouth with a yellowish, not thin, cuticula. The tongue with 
rine rows of teeth, in the rasp-sheath also eleven rows of developed 
and two of not quite developed teeth, the total number thus being 
twenty-two. In the posterior rows of the tongue the number of plates 
was twenty-eight or twenty-nine, on each side, and seemed in the suc- 
ceeding rows not to surpass thirty. The color of the teeth horn- 
yellowish ; the height of the outermost 0.06 to 0.08 mm., the height 
rising to about 0.18 mm. ‘The form of the teeth as usual; the wing 
rather narrow; the innermost (fig. 5aa, b) not very different from the 
