Boone, Mollusca, Cruises of "Ara" and "Alva" 329 



of the siphon and concave medially between these two points. 

 The caudal fins are trapezoidal with rounded angles, being shorter 

 on the paired anterolateral margins than on the posterolaterals. 

 In the two larger specimens, the caudal fins occupy a little more 

 than one-half of the body length, but in the smaller specimen the 

 caudal fins equal little more than one-third of the body length. 

 The exposed portion of the siphon is short, broad, rounded, with 

 a moderately broad aperture. The head is slightly wider than long, 

 dorso-ventrally compressed, rounded; the eyes are large, lateral. 

 The arms decrease in length in the order 3, 4, 2, 1, with the third 

 and fourth pairs dorsally webbed. The suckers of the sessile arms 

 are moderately large, pedunculate, set obliquely, in two rows ap- 

 proximately, with the lateral margin on either side marginally 

 produced into a thin ribbon-like webbing. The suckers of the third 

 pair are distinctly larger than those of the other pairs of arms. 

 The horny ring of one of these large suckers has eight to nine 

 short, square-cut, close-set teeth on the distal side, the proximal 

 half being smooth. The hectocotylus is not present. 



The outer buccal membrane is produced into five decided 

 points, each of which bears a cluster of 2, 3 or 4 small suckers ; the 

 two ventral points are curtailed. Within the margin of the mem- 

 brane, in the median ventral area are numerous small papillae, 

 for the attachment of spermatophores. Both membranes are 

 much folded, the inner one fitting closely around the beak. The 

 beak is of the usual Loligo type, very powerful. 



The tentacular arms (even in dead specimens) are exceedingly 

 long, being one and one-half times the combined length of the body, 

 head and sessile arms. The tentacular arms are very slender, sub- 

 cylindrical, with the distal fourth supporting the club, which is 

 little expanded, narrowly ovate in contour, with the lateral mar- 

 gins produced into a ribbon-like protective margin; externally 

 the club bears a well defined web. The suckers are set in approxi- 

 mately four series, there being 18 to 20 proximally; small, but 

 distally gradually increasing in diameter. There are eight to ten 

 large median suckers, each of which is about twice the diameter 

 of the adjacent alternating lateral suckers ; beyond these there are 

 about twenty to twenty-two smaller suckers, continuing the four- 

 row arrangement and gradually decreasing in size toward the tip. 

 The small cups are set obliquely, the larger ones but little so and 

 have the free margins marked by radial lines ( ? possibly due to 



