122 BULLETIN OF THE 



the arms are but little elevated, and have verv broad bases ; thev alternate re^u- 

 larly, and their borders ai-e nearly or quite in contact. The three suckers next 

 the mouth on each arm are nearly in one line ; the smaller inner ones forming 

 a regular circle around the mouth. 



In the male, the right arm of the third pair is hectocotylized. This arm is 

 decidedly shorter than its mate, and tapers much more rapidly to the tip, which 

 is acute ; along the posterior dorsal angle of the arm there is a strong, broad 

 memliranous fold, with the lower surface strongly concave, white, and crossed 

 liy numerous distinct transverse grooves ; the outer edge of the membrane is 

 thin, sharp, white, and curves inward over the grooA'e. The groove with its 

 covering membrane extends close to the tip of the arm, where it terminates in a 

 minute conical papilla ; beyond this, there is a minute, conical, naked tip, but 

 without any appearance of the spoon-shaped cavity and transverse grooves 

 found in other species of Octopus. 



In alcoholic specimens the entire upper surface is usually very dark purplish 

 brown, varying to dark bluish gray. In some specinu'iis there are obscure 

 patches of darker and lighter over the upper surface. In all the specimens 

 examined there is a large, rounded, purplish black spot near the base of the 

 web, and corresponding to the interval between the second and third pairs of 

 arms. Lower surface of the body, head, and web nmch lighter than the upper 

 surface, dull grayish or yellowisli white, finely specked with purplish chro- 

 matophores. Terminal portion of the siphon darker, much like the dorsal sur- 

 face, inner surface of the web and arms grayish purple, pah;r than thi^ upper 

 surface. Inner surface and rim of the suckers yellowish while. 



The largest male observed (from San Diego, Cal.) has the dorsal arms 325 

 and 390 mm. long, from the mouth; second pair of arms, 540 and 450 mm. 

 long; third pair of arms on left side, 550 mm.; right (hectocotylized) arm, 

 400 mm. ; ventral arms, 500 and 490 mm. ; greatest transverse diameter of the 

 dorsal arms, 20 mm.; lateral arms, 25 mm.; ventral arms, 20 mm.; diameter 

 of the larger suckers of the lateral arms, 11 to 14 mm.; of the twelfth sucker, 

 15 to l(i mm.; l)readtli of the web between dorsal arms, from the mouth, 

 GO mm.; between lateral arms, 70 to 100 mm.; between ventral arms, GO mm.; 

 length of body, 70 mm.; greatest breadth, 75 mm.; vertical thickness, 42 mm.; 

 breadth of head across eyes, 45 mm.; breadth of dark spot at base of web, 

 20 nmi. 



A somewhat smaller male, with the tissues more contracted, has the dorsal 

 arms 2G5 mm. long ; second pair of arms, 270 mm. (probably reproduced) and 

 280 mm. ; third pair of arms, 300 mm. (left side) ; hectocotylized arm, 2G5 mm. ; 

 ventral arms, 285 mm.; dianietei' of tlie twelfth sucki-r of ihc lateral arms, 20 

 to 22 mm.; of the adjacent suckers, 12 to 14 mm.; length of liody, 70 mm.; 

 breadth, 60 mm.; breadth of head, 45 mm. 



This species has an extensive southern distrilnUion on the Pacific coast. It 

 is comnKjn at San Diego, California, where it has been obtained by Dr. Edward 

 Palmer and others. Numerous small specimens were obtained at Panama and 

 on the c^.ast of SaTi Salvador bv ^fr. Frank If. Pradh-v, for tlie Museum of 



