230 A. E. Yerr ill — North American Cephalopoda. 
The largest of all the suckers are near the middle of the second pair 
of lateral arms, from the sixth to the sixteenth, and especially from 
the ninth to the fourteenth; the diameter of the ninth is 10 mm , the 
edge of its rim, 8 mra . On the dorsal arms the eighth to the thirteenth 
are the largest ; the diameter of the ninth is 7 ranj ; edge of horny rim, 
5"im O u the third pair the eighth to the fourteenth are largest; the 
diameter of the tenth is 8 mm ; its rim 6 mm . On the ventral arms the 
fourteenth to the twentieth are largest; the diameter of the fifteenth 
is7'5 rnnj ; its rim 5’5 mm . On the ventral arms the rows of suckers 
are more separated than on the others, its inner face being wider. 
On the lateral arms, toward the base, the two rows are nearer to- 
gether, while the suckers of each row are distant, so that they almost 
form one irregular row, at first. The suckers are all very oblique, 
with the horny rims very low or narrow in front, and very high on 
the outer side ; these rings are dark brown, but the teeth have a 
golden luster. 
The thick fleshy margin, outside the denticulated edge of the horny 
ring, is completely covered all around, by a series of thin, bracket- 
shaped, horny plates, light brown in color, arranged radially and 
movable with the membrane to which they are attached for the 
most of their length ; both the outer and the inner ends are free and 
turned upward, like a small tooth or denticle ; those of the inner end 
are mostly acute, and form a circle of minute movable denticles, 
nearly in line with the large teeth of the horny ring, five to ten occu- 
pying the intervals between the large teeth of the largest suckers; 
those plates that stand opposite the teeth of the horny ring are 
shorter than the others, and often broader, and have no denticle on 
the flat or upcurved inner ends, which fit to the form of the base of 
the tooth in front of them ; the outer ends are abruptly bent upward 
and often inward, forming a denticle or flattened hook, usually 
rounded at the end. These marginal plates vary greatly in width 
and form, even on the same sucker, according to position, and small, 
imperfectly developed, wedge-shaped ones are interpolated between 
the larger ones, around the periphery. 
One of the largest suckers (the twelfth of the second pair of arms) 
has 22 teeth on the horny ring ; of these five are small, but sharp, on 
the middle of the inner border ; nine, on the outer border, are largest ; 
and four, on each side, are intermediate in size. The median tooth on 
the outer margin is largest, and the one next to it, on each side, is a 
little smaller than the second one from it. The thirteenth sucker of 
the ventral arms has, on its rings, eighteen denticles ; of these nine 
