88 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



Genital slits long, but not conspicuous; genital scales short, but very 

 wide distally with a well-marked supplementary scale at proximal 

 end ; each genital scale (with its supplementary scale) carries a mar- 

 ginal series of about twenty-two papillae, which are flat, truncate, and 

 crowded below, but become longer, more spine-like, and better spaced 

 above. First under arm plate somewhat triangular or tetragonal, 

 with distal margin much longer than proximal; succeeding four or 

 five plates squarish, wider than long; remaining plates tetragonal, 

 longer than wide, becoming ultimately very minute and triangular; 

 all under arm plates are in contact until near tip of arm. Side 

 arm plates not very large, well separated both above and below; 

 each plate carries two true arm spines; one near upper corner of 

 plate, not very flat, sharp, about one-third as long as arm joint; 

 the second, low down on plate, very flat, somewhat pointed, not 

 always to be easily distinguished from underlying secondary series; 

 this secondary series of arm spines is very well developed and 

 is made up of flat, truncate, crowded papillae which are much 

 longer near middle of plate than they are either above or below; 

 lower papillae largest, not always to be easily distinguished from 

 outermost tentacle scales. Oral tentacle pores do not quite open into 

 mouth slits; they are protected by about four scales on, each side. 

 Basal tentacle pores of arm with four to eight scales on proximal side, 

 but only three or two small ones on distal side; after about fourth 

 pore there are no scales on distal side, though there may still be five 

 or six on proximal side; near tip of arm there are simply two small 

 scales on proximal margin of each pore. Color (dried from alcohol), 

 yellowish-brown or fawn color. 



Localities. Albatross station 5018, off Sakhalin, lat. 46 41 ' 30" 

 N.; long. 143 57' 40" E., 100 fathoms, brown mud, black sand, peb- 

 bles, bottom temperature 30.4, 1 specimen; station 5023, off Sagha- 

 lin, lat. 48 43' 30" N.; long. 145 3' E., 75 fathoms, sand, pebbles, 

 bottom temperature 30.9, 1 specimen. Bathymetrical range, 75 to 

 100 fathoms. Temperature range, 30.9 to 30.4. 



Type. Cat. No. 25548, U.S.N.M., from station 5023. 



This is still another species of the stereo, group, easily distinguished 

 by the secondary arm spines. It is somewhat doubtful whether the 

 peculiar arrangement of the .disk scales shown by these two speci- 

 mens will really prove sufficiently constant to afford a specific char- 

 acter; if it should prove constant, it would be very useful as an easy 

 means of recognition, even apart from the secondary arm spines, for 

 I know of no other species in which the centrodorsal is so small in pro- 

 portion to the radial plates. The extremely low temperature of the 

 water is a marked feature of the habitat of this species. 



