[29] CEPHALOPODS OF NORTHEASTERN COAST OF AMERICA. 239 



ers. Here the arm is flattened on the face, rounded on the back, and 

 provided with a sharp dorsal carina, increasing in width toward the tip. 

 It bears two alternating rows of about twelve very large, serrated suck- 

 ers, and an outer row of smaller ones, on each side, alternating with the 

 large ones. The upper edge is bordered by a rather broad, regularly 

 scalloped, marginal membrane, the scallops corresponding" to the large 

 suckers, while prominent transverse ridges, midway between the large 

 suckers, join the membrane and form its lobes. On the lower edge 

 there is a narrower and thinner membrane, which runs all the way to 

 the tip of the arm. In one (the lower) of the rows of large suckers there 

 are eleven, and in the other ten, above 20 mm in diameter. The former row 

 has one additional sucker at its proximal end, 15 ram in diameter, and 

 three others at its distal end, respectively 16 mm , 12 mm , and 8 mm in diameter. 

 The other row, of ten suckers, hi continued by a proximal sucker 10 mm in 

 diameter, and by two distal ones, respectively 15 mm and 13 ram in diameter. 

 The number of large suckers in each row may, therefore, be counted 

 as 12, 13, or 14, according to the fancy of the describer, there being no 

 well-defined distinction between the larger and smaller ones in either 

 row. The largest suckers, along the middle of the rows, are from 24 mm 

 to 30 mm in diameter (Plate IV, fig. 4, a). They are attached by slender but 

 strong pedicels, about 10 mm long and 6 mm to 7 mm in diameter. The outer 

 or back side of these suckers is 16 mra to 18 mm high; the inner side 10 mm to 

 ll mm , so that the rim is about 24 nm to 28 mm above the surface of the arm. 

 The horny rings are 7 mm to 8 mm high and have the aperture 20 mm to 23 mm in 

 diameter. Each one is situated in the center of a pentagonal depressed 

 area, about 25 mm across, bounded by ridges, which alternate regularly 

 and interlock on the two sides, so as to form a zigzag line along the mid- 

 dle of the arm. These large suckers are broadly and obliquely campan- 

 ulate, but much less oblique than those of the short arms; the marginal 

 ring is strong, and sharply serrate all around; the denticles are acute- 

 triangular and nearly equal. The rings are somewhat calcified and 

 rather rigid when dried; a well-marked broad groove runs around the 

 entire circumference, below the bases of the denticles. 



The small marginal suckers (fig. 4, b) are similar in structure, but much 

 more oblique, and mostly 9 mm to ll mm in diameter; they are attached by 

 much longer and more slender pedicels, and their marginal teeth are 

 relatively longer, sharper, and more incurved, especially on the outer 

 margin. The peripheral groove is broad and deep, but is interrupted on 

 the outer side for about a third of the circumference; the outer third 

 portion of the horny ring is somewhat flattened from the circular form. 



The terminal division (hi to iv) of the arm is 22.8 CI " long. It gradually be- 

 comes compressed laterally, and tapers regularly to the tip, which is flat, 

 blunt, and slightly incurved. Just beyond the large suckers, where this 

 region begins, the circumference is 9 cm . The face is narrow and bears a 

 large number of small pediceled suckers (Plate IV, figs. 10, 10 a), ar- 

 ranged in four regular, alternating rows, gradually diminishing in size 



