168 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.57. 



DESCRIPTION OF SPECIES. 



Suborder OCTOPODA Leach. 



Division LIOGLOSSA Liitken. 

 WATASELLIDAE, new family. 



WATASELLA, new genus. 

 1. WATASELLA NIGRA, new species. 



Plate 23, fig. 1. 



Station 4977 (off Kii Province). One specimen. 



Animal soft, choroidal, translucent, covered by a flabby and smooth 

 skin throughout. Mantle thick, saccular, a little longer than broad, 

 widest anteriorly, rounded posteriorly. Mantle-opening wide, extend- 

 ing half round the body. Fins, two pairs in number, those of each 

 pair attached side by side to the dorso-lateral surface of the mantle 

 much nearer to its posterior end than to the anterior margin; the line 

 of attachment being longitudinal. Transverse length of fins equal 

 to about twice their breadth and a quarter of the length of the 

 mantle. 



Head large, subcylindrical, as broad as the body, with no constric- 

 tion in front or behind. Eyeball dark violet in color, openmg on 

 the exterior through a large orifice. Tuberculus oifactorius of pink 

 color, present on each side of the neck region a little before and below 

 each angle of mantle-opening. 



Arms subequal, on an average about as long as the head and mantle 

 taken together; cylmdrical in the proximal half, then tapermg distad 

 to the attenuated extremities. Umbrella tliick, broad, extending half 

 way vep the arms, apparently without nodule at the termhiation of 

 its attachment. The suckers number ten or more ui each arm, set 

 uniserially on its distal half; globular but depressed at the distal end, 

 which has a minute aperture at the center; deeply constricted at base 

 so that they approach in appearance the pedunculate suckers of deca- 

 pods. Cirri biserial, alternating with the suckers, but ten or tvrelve 

 more are found proximal to the first sucker on each arm. 



A tubular pouch exists betv/cen the first and second arms on either 

 side, running radially through the umbrella, and opening externally on 

 the umbrella edge. The pouch has a filamentous organ growing 

 from its blind end. 



Beak strong, very large. Radula not examined. 



Color of mner surface of umbrella in formalin, quite black; external 

 surfaces of all parts apparently also of the same color, except the 

 mantle edge, which is of reddish hue. Tuberculus oifactorius, inner 

 and outer lips, the distal part of suckers and cirri all of a light crimson. 



Total length 25 mm.; ventral length of mantle 8.3 mm. 



Type.— C&t. No. 332892, U.S.N.M. 



