318 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [108] 



they have a smaller crest along the outer angle, and a narrow membrane 

 along each inner angle. 



All the sessile arms bear similar suckers (Plate XVII, figs. 8, a-c), all 

 of which are provided with 7 to 13 large, very acute, incurved teeth on 

 the outer margin of the very oblique horny rings, and with much smaller, 

 sometimes rudimentary ones on the inner margin, much as in 8. megaptera. 

 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 mm . On the dorsal arms the eighth to the thirteenth are the 

 largest ; the diameter of the ninth is 7 mm ; edge of horny rim, 5 mm . On 

 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 is 7.5 mm , its 

 rim 5.5 mm . On the ventral arms the rows of suckers are more separated 

 than on the other arms, their inner faces being wider. On the lateral 

 arms, toward the base, the two rows are nearer together, while the suck- 

 ers 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 (fig. 9), 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 occupying 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 hood, usu- 

 ally 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 

 (fig. 8, b, &'), 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 ring, eighteen denticles ; of these nine 

 are very large, with the median more decidedly the largest, and the one 



