262 A. M Verrill — North American Gephalopods. 



At first there are 8 to 10 denticles on the outer margin, but these 

 diminish in number as the suckers diminish in size, till at about 6 

 inches from the tip there are mostly but two or three, and the aper- 

 ture is very contracted. Still nearer the tip there are but two, blunt 

 ones ; then these become reduced to a single bilobed one ; and finally 

 only one, which is squarish, appears in the minute suckers of tlie last 

 two inches of the tip. The first two or three suckers at the base of 

 the arm are more feebly denticulated than those beyond, with smaller 

 apertures. 



On many of the suckers (Plate XXXVIII, fig. 3) there are still 

 remaining, in more or less complete preservation, a circle of minute 

 horny plates arranged radially, or transversely, on the edge of the mem- 

 brane around the aperture, similar in arrangement to those already 

 described in the former part of this article (p. 230) on the suckei-s of 

 Sthenoteuthis jyteroptis (Plate XXXVI, fig. 9). They are less devel- 

 oped, however, than in that species, being thinner and more delicate, 

 nor do their ends appear to turn up in the form of hooks. They 

 seem to be generally very thin, oblong, scale-like structures, with 

 rounded or blunt ends and slightly thickened margins. These struc- 

 tures will probably be found to vary with age, and perhaps with the 

 season. They appear to be easily desiduous, and are often absent in 

 preserved sjjecimens. 



On the dorsal and third pairs of arms the suckers have essentially 

 the same arrangement, form and structure, and on these three pairs 

 of arms the larger suckers differ but slightly in size. The character 

 and arrangement of the suckers on the distal portion of these arms is 

 well shown on Plate XXVI, figs. 3, 3«, which represent a portion of 

 one of the third pair of arms, commencing at the 67th sucker. 



The ventral arms are trapezoidal in section, at base, and rather 

 stout. Breadth of front surface, near the base, exclusive of mem- 

 branes, -55 ; transverse diameter, -95 ; front to back, 1*25 inches. The 

 sucker-bearing surface is, therefore, broader than in the other arms. 

 The suckers are, however, distinctly smaller and the proximal ones 

 are different in form from the corresponding ones on the other arms. 

 They are narrower and deeper, with more oblique and more con- 

 tracted apertures, more oblique horny rims, which are denticulated 

 on the outer margins only. On the larger ones there are 12 to 15 

 sharp incurved denticles. In fact, the proximal suckers on the ventral 

 arms agree better with the middle suckers, beyond the 30th, on the 

 other arms, for there are none having wide open apertures, sur- 

 rounded by nearly even horny rims, denticulated all around. The 



