272 A. M Verrill — North American Cephalopods. 



The portion of the tentacles wliich bears suckers is always less 

 than half the whole length. The relative size of the suckers varies 

 greatly in both sexes, perhaps in connection with a periodical 

 renewal of their horny rings. 



The club is long and moderately broad, gradually widening from 

 the peduncular part of the arm, and tapering at the end to a rather 

 blunt, flattened and curved tip, which is strongly carinated on the 

 outer side by a thin lamina. The suckers commence a short distance 

 in advance of the expansion of the club. They are at first small, 

 deep cup-shaped, and somewhat scattered, in two alternate rows, but 

 all of these small ones have oblique rims, strongly denticulated 

 on the outer margin with four or five long incurved teeth, while the 

 inner edge is smooth. Of the small ones, before the commencement 

 of the two median rows of lai-ge suckers, there are from ten to fifteen. 



The middle region of the club is occupied by two rows of large 

 suckers (fig. 7) and by a row of small marginal ones, on each side, 

 alternating with the large ones. The uppermost of the two rows of 

 large suckers contains one or two more suckers than the lower, and 

 they are also larger. The number in the upper row is seven to nine, 

 in the lower five to seven, the largest specimens having the greater 

 number. Of these, the three to five middle ones in each row are 

 decidedly the largest and have the edge of the marginal ring nearly 

 smooth and even ; at each end of each row the suckers diminish in 

 size and the edge becomes denticulate, at first by the formation of 

 narrow incisions, which leave broad, stout, blunt denticles ; but as 

 the suckers diminish in size these become longer, narrower and more 

 acute ; their inner margins remain smooth. The large suckers are 

 broad and moderately deep, somewhat swollen below, and a little 

 oblique. The marginal suckers are much smaller, shallower, more 

 oblique, and have the entire rim finely and sharply denticulate, the den- 

 ticles being longer and strongly incurved on the outer margin. Beyond 

 the rows of large suckers there is, at first, a small group of sharply 

 denticulate suckers, in four rows, resembling the marginal ones in 

 form and size ; but these rapidly decrease in size and are succeeded 

 by eight crowded rows of very small suckers, with minute apertures, 

 which occupy the entire face of the terminal section to the tip. 



The suckers of the sessile arms are largest on the two lateral pairs, 

 on which they are nearly equal, and the largest are about the same 

 in size as those on the tentacular-club ;* those of the ventral arms are 

 smallest ; those of the dorsal arms are intermediate in size between 



* In the males the tentacular suckers are usually the smaller ; in the females often 

 the larger. 



