REPORT ON THE ASTEROIDEA. 611 



Locality. — Station 237. Off the coast of Japan, south of Kawatsu. June 17, 1875. 

 Lat. 34° 37' 0" N., long. 140° 32' 0" E. Depth 1875 fathoms. Blue mud. Bottom 

 temperature 35°"3 Fahr. ; surface temperature 73 o, Fahr. 



Remarks. — The specimen above described consists of the disk and two entire rays, 

 with portions of two others. At first sight its characters vividly recall those of Brisinga 

 endecacnemos, but the species is readily distinguished by the smaller number of rays, by 

 the character of the adambulacral armature, by the extraordinary delicacy of the abactinal 

 membrane, and by the simplicity of the covering of the disk ; the lateral margin of the 

 disk is also distinctly bevelled in contrast to the more precipitous wall in Brisinga 

 endecacnemos. 



6. Brisinga membranacea, n. sp. (PI. CX. figs. 8 and 9). 



Disk and number of rays unkuown. R = 75 mm. Breadth of a ray at the base, 2 - 5 

 mm. ; at the widest part of the ovarial inflation, 3 mm. (measured at 12 mm. from the 

 base of the ray) ; and midway between the extremities, 175 mm. 



Rays elongate, slender, and tapering to a fine extremity, but they appear to be compara- 

 tively short in proportion to their robustness as compared with the majority of the species of 

 Brisinga ; subcylindrical and depressed at the base, thence swelling slightly and gradually 

 into a very feebly developed ovarial inflation and as gradually contracting, the widest 

 part being comparatively far removed from the base of the ray, which causes the ovarial 

 re<non to appear to occupy quite the inner third of the length. Outward beyond this 

 point the ray is subtriangular. 



The abactinal surface of the ray is covered with an extremely thin and delicate 

 membrane. On the inner third or fourth of the ray, that is to say on the ovarial region, 

 there are a few irregularly disposed transverse annular calcareous ridges, eight or nine in 

 number. These are remarkably narrow, and formed of very delicate elongate ossicles, 

 some of wdiich bear short, delicate, hair-like microscopic spinelets. Between the calcareous 

 ridges and along the ray beyond the ovarial region are saccular transverse bands or areas 

 crowded with small pedicellariae. 



The ambulacral furrow is wide and measures 1"5 to 1*75 mm. at a part where the ray 

 is 2 - 75 mm., about 10 mm. from the base of the ray. The adambulacral plates are longer 

 than broad, measuring 175 mm. at 10 to 15 mm. from the base of the ray; they are 

 considerably constricted midway between their extremities, and the furrow-margin is 

 distinctly concave. The adambulacral armature consists of: — (1.) one small inner spinelet 

 directed horizontally over the furrow ; (2.) a small actinal spine, standing perpendicularly 

 on the actinal surface of the plate ; (3.) a moderately long lateral spine, normally corres- 

 ponding to every alternate plate, articulated on a small independent marginal plate. The 

 small inner spine is attached near the aboral end of the plate, and is situated quite within 



