200 A. E. Yerrilt — N<yrth American Cephalopoda. 
22‘9, 20*3 and 17‘8 cm (ten. nine, eight and seven inches) in circumfer- 
ence.* They are, except the ventral, compressed trapezoidal in form 
and taper very gradually to slender acute tips. Their inner faces are 
occupied by two alternating rows of large obliquely campanulate 
suckers, with contracted apertures, surrounded by broad, oblique, 
thin, horny, marginal rings, much broader on the outer side than on 
the inner, and armed with strong, acute teeth around their entire cir- 
cumference, but the teeth are largest and most oblique on the outside 
(Plate XVI, tig. 4 ; XYIcr, tigs. 6-8). These suckers gradually dimin- 
ish in size to the tips of the arms, where they become very small, but 
all that are preserved are similar in form and structure. The ventral 
pair of arms still have, as they show in the photograph, the inner face 
much broader than it is in the others, especially near the base, and 
they are more nearly square than any of the others. Their suckers 
are more numerous, farther apart transversely, and closer together in 
the longitudinal series, there being about 46 on the proximal half (36 
inches) of each, while on each of the subventral arms there are only 
about 30 on the corresponding portion ; the suckers also diminish 
rather abruptly in size at about 26 to 30 inches from the base, beyond 
which they are scarcely more than half as large as those on the 
second and third pairs of arms, at the same distance from the 
base. The largest of these suckers are said, by Mr. Harvey, to have 
been about an inch in diameter, when fresh. The largest of their 
marginal rings, in my possession, are 14 mm to 16 rara in diameter, at 
the serrated edge, and 18 ram to 20 mni beneath. 
The homy rings are yellowish horn-color, oblique, and more than 
twice as wide on the back side as in front. A wide peripheral groove 
runs entirely around the circumference, just below the denticulated 
margin ; it is narrower and deeper on the front side. On the front 
side the edge is nearly vertical, and the denticles point upward or are 
but slightly incurved ; but on the outer or back side the edge and 
denticles are bent obliquely inward ; along the side the edge is more 
or less incurved and the denticles are inclined more or less forward, 
toward the front edge of the sucker. The denticles are golden 
yellow, or when dry, silvery white ; those on the outer and lateral 
* In the original statement it is not mentioned to which pairs of arms these dimen- 
sions apply. After having been five years in alcohol the ventral arms now measure 
7 5 inches in circumference, and one of the lateral ones (perhaps one of the third pair) 
8 inches. The marginal membranes or crests had decayed, apparently, before the 
arms were preserved : their terminal portions are also gone, so that the real length 
cannot be given. 
