86 U.S. NATIONAL MUSEUM BULLETIN 234 



Description. — The mantle is long and slender, about a fifth as 

 wide as long, ending posteriorly in a sharp point. There is a small 

 lappet in the dorsomedian line anteriorly and a shallow excavation 

 beneath the fminel with sharp angles on each side. In the males 

 there is a ventromedian ridge on the anterior three-fourths of the 

 mantle; the females are smooth. 



The funnel is small, stout, nearly covered by the mantle. The 

 locking apparatus is straight and simple. The funnel organ is of 

 the usual type and there is a large subterminal semicircular valve. 



The fins are small, about 50 percent of the mantle length in the 

 males, less in the females. They have very small anterior lobes, 

 straight anterior edges, rounded angles, and concave posterior edges. 

 They are united just dorsal of the posterior end of the mantle. 



The head is small, slightly wider than the mantle, with large eyes 

 and a slight constriction at the base of the arms. There is also a 

 small straight-edged groove in the median dorsal surface. There is 

 a large crest posteriorly and a small anterior pore near the base of 

 arm III. The head is flattened and is deeply and distinctly excavated 

 ventrally for the funnel. 



The arms are short, about 25 percent of the mantle length, in the 

 order 3.4.2.1, although in the males the left ventral arm may be the 

 longest, especially in the larger specimens. Arm I is very flattened, 

 short, and provided with a high keel along its entire length. II is 

 squarish with a sharp keel or low membrane on both outer corners, 

 the ventral the deepest. Ill is flattened and equipped with a broad 

 swimming membrane, or keel. IV is also square in cross-section 

 with a pronounced keel dorsally and ventrally. The arm suckers are 

 in two rows bordered on each side by a trabeculate protective mem- 

 brane which, except in IV, is deepest on the ventral side. The 

 suckers in both sexes have the horny ring smooth on the proximal 

 margin and armed with about seven long narrow square-tipped teeth 

 on the distal margin. 



In the males both ventral arms are hectocotylized. The left 

 ventral arm is longer than the right and broader, because of the wide 

 ventral and dorsal keels which do not taper to a point distaUy. Bas- 

 ally, in the holotype, there are 19 suckers of the normal tjq^e, becoming 

 smaller towards the last pair; beyond this, for more than half the length 

 of the arm there are about 22 pairs of long round papillae or pedicels 

 each terminating in a minute ringless sucker. Pairs 2 to 7 of these 

 are much longer than the remaining pedicels. Beyond the terminal 

 pedicels, the tip of the arm projects as a smooth round cone. The 

 right ventral arm is shorter than its fellow. The suckers are normal 

 basally, but pairs 8 through 15 diminish rapidly in size; beyond pair 

 15 the suckers disappear and only a double row of minute pedicels is 



