EXPLORATION OF ALASKA. 253 
The form elongate-oval. The back covered all over with irregular 
(the greatest height reaching about 1.5 mm.), conical, rather soft and 
flexible papillw, in general larger than in the typical species. The 
margin of the rhinophor-holes thin, somewhat prominent, with two 
anterior strong tubercles and a posterior much smaller one; the stalk 
of the club rather low, the latter with about twenty-five to thirty leaves. 
The branchia consisting of nine to ten leaves, the adjacent border set 
with several strong tubercles; the branchial leaves quite isolated at 
their base, apparently simply pinnate. The anus prominent, before 
the same a small tubercle, behind it a much larger one. The margin 
of the mantle rather thin, on the upper side covered with a mass of 
smaller and larger papilla and tubercles, the under side smooth. The 
head broad, flat, with prominent rounded, flattened tentacula. The 
foot broad, rounded behind. 
The central nervous system as in the typical species; the buceal 
ganglia rounded, the commissure between them very short. The eyes 
with black pigment and yellow lens. The otocysts a little smaller 
than the eyes, with numerous otokonia of the usual form, and reaching 
a length of 0.03 mm. The leaves of the rhinophoria without spicula ; 
in the axes of the organs large, molecularly calcified cells and groups 
of smaller calcified cells. In the papille of the skin of the back were 
no spicula at all, on their surface the usual large quantity of glandular 
cells ; in the skin beneath the papilla cells and groups of cells as in the 
case of the rhinophoria. 
The mouth-tube rather wide, with strong cuticula. The bulbus 
pharyngeus formed apparently as in the typical species; the lip-plate 
composed of many rows of rather low (the height rising to about 
0.02 mm.), very (fig. 6) finely striated columns. The tongue with ten 
rows of teeth; further back, twenty-six developed and three undevel- 
oped rows; the total number thus thirty-nine. The lateral plates 
large, yellow, of usual form, with a series of denticles along nearly 
the whole of the inner margin of the hook (fig. 16a). The external 
plates colorless, eight in number; somewhat depressed (fig. 7, 16), 
obliquely rising from the cuticula of the tongue (fig. 7), of nearly equal 
size excepting the outermost (fig. 160), which is much smaller. 
The salivary glands seemed of the usual form. The cesophagus and 
the stomach as usual. ‘The intestine issuing from the liver at the 
middle of its length on the left side, rather short. The liver of the 
length of about 9.0 mm. by a breadth and a height of about 4.2 mm. ; 
