450 Mr. E. S. Russell on the Cephalopoda 



The actual visceral sac is very small, being narrowly 

 triangular and not extending back much beyond the insertion 

 of the fins. The gills are very long and slender. 



The mantle is covered with small pale red chromatophores, 

 which are present also on the dorsal aspect of the fins. The 

 head is more deeply coloured in shades of brown and crimson, 

 the chromatophores being aggregated especially at the antero- 

 ventral border of the eye. The eye is covered over by a skin 

 set with chromatophores and resembling the skin of the head. 

 In front there is a deep transverse groove with puckered edges; 

 it is 3 mm. long, has a muscular margin, and marks the 

 opening from the anterior chamber of the eye to the exterior. 



Chromatophores are present also on the arms and tentacles. 



The order of the arms is 2, 3, 4, 1. They are without web 

 or keel, except the ventral pair, which have a narrow fin on 

 their extero-ventral edge. The second pair are about two- 

 thirds the length of the mantle. The suckers are in two 

 slightly alternating rows, and they are not continued right 

 down to the mouth, 2-3*5 mm. being without suckers. The 

 cups of the suckers are nearly globular, inserted very ob- 

 liquely on pedicels, slender above, swollen below. The horny 

 ring is higher above, has 5-8 square teeth on its upper half, 

 and is smooth on its lower half. 



On the second and third arms, and to a less extent on the 

 first arms also, the swollen part of the pedicels of the external 

 row of suckers gives off a slender cirrus, whose length may 

 equal the diameter of the cup. The cirri are not free, but are 

 bound to the arm throughout their length by a fold of thin 

 skin. Tentacles are fairly stout, 60 mm. in length, more or 

 less triangular in cross- section. The club is 13 mm. long, 

 5 mm. broad, and is thin and flattened from above down- 

 wards for 10 mm. of its length, then at the tip the plane of 

 the club is twisted inwards through a right angle, so that its 

 ventral surface becomes vertical and looks inwards. This 

 terminal part is 4'5 mm. long and has a thin vertical sucker- 

 less crest. The axis of the tentacle is not itself expanded to 

 form the club, the lateral portions of whicii are formed rather 

 by the long pedicels of the marginal suckers, which are 

 bound together in a membranous expansion of the axis. In 

 the terminal portion the axis is without suckers, but its 

 ventral expansion bears three rows, of which the lowest are 

 the largest. At the twist of the club there are two irregular 

 transverse rows of large suckers, about five suckers in each 

 row. These are the largest suckers on the club. The main 

 body of the club bears on its ventral surface numerous thin- 

 stalked minute suckers irregularly disposed in about 12-15 



