244 A. E. Verrill—Mollusca of the New England Coast. 
being about twice the length of the sessile arms, and not half as thick 
at the base as the smallest of the sessile arms. The proximal half is 
strongly flattened, and tapers from the base outwardly. The distal 
half is much more slender and is somewhat angular or triquetral, 
becoming somewhat sub-cylindrical and very slender toward the 
club, which is well developed, narrow-lanceolate in form, somewhat 
expanded toward the base, and gradually tapered to the tip. The 
slender distal half of the arm bears a row of very small, rather dis- 
tant, smooth edged, sessile suckers, alternating with minute tubercles 
on its inner surface; these are evidently intended, as in allied genera, 
for attaching the two arms together. Close to the base of the club, 
these sessile suckers become closer and more numerous. The club 
itself bears, on its broader, basal portion, about six rows of suckers. 
One row, which is nearly central, consists of about seven, rather 
broad, cup-shaped suckers, decidedly larger than any of the others, 
and of these, three central ones are decidedly the largest ; their horny 
rings are very finely and sharply denticulate around the entire margin, 
which is but little oblique; just below the horny ring there is a con- 
striction, and the body of the sucker is considerably swollen. Alter- 
nating with these are other similar, but smaller, suckers, forming a 
second median row; on each side of these are two marginal rows of 
still smaller and somewhat more oblique, cup-shaped suckers. The 
distal half of the club is crowdedly covered with numerous, small 
suckers, which are apparently arranged in six rows, and decrease 
gradually in size to the tip of the club, the number of rows appar- 
ently decreasing to four, and the size becoming very minute near the 
tip, which is very narrow, simple, and, in this specimen, strongly 
curled spirally. These tentacular arms differ in color from the rest 
of the arms, the imer surface being orange, the edges yellowish 
white, and the outer surface covered with definite orange-brown 
chromatophores, while the other arms are darker externally, owing 
to the much more crowded chromatophores, and are covered with 
prominent verruci, each of which is marked on one side with dark 
brown, while the tip is white; the inner surface of the sessile arms 
is deep brown, and the suckers are white at base, tinged with orange- 
brown near the margin. The general color of the body and head is 
like that of the outer surface of the arms, but as in the original speci- 
men, the color is much deeper and the verrucze more numerous on 
the ventral surface than above. The caudal fin is thin, translucent, 
and destitute of color, except close to the base, where there are a few 
orange-brown chromatophores. The lobes of the fin extend back 
