626 THE VOYAGE OF H.M.S. CHALLENGER. 



borne upon it, usually in the region of the swelling, or extending towards the base, the 

 distal extremity being left free. A robust-looking secondary spine, 4 mm. in length, is 

 placed well back on the surface of each plate. These spines stand perpendicularly, and are 

 encased in a membranous sheath with crowded pedicellarise, precisely similar to the large 

 perpendicular spine in the adambulacral armature throughout the ray. 



The ambulacral tube-feet are short and stout, tapering a little towards the distal 

 extremity, which terminates with a well-defined and centrally deeply invaginated terminal 



disk. 



The madreporiform body, though small, is remarkably conspicuous on account of being 

 prominent and almost semigiobular. Its outline is circular, 2'5mm. in diameter, and it is 

 situated at about the same distance from the margin of the disk. There are only about half- 

 a-dozen deep, widely spaced striations upon its surface ; some, which are simply wavy, 

 traverse the area, whilst others are convolute, their disposition being altogether irregular 

 and without any approach to centrifugal radiation. 



Colour in alcohol, a bleached yellowish white, the disk with a slightly brown shade. 



Localities. — Station 205. West of the Island of Luzon, Philippine group. November 

 13, 1874. Lat. 16° 42' 0" N, long. 119° 22' 0" E. Depth 1050 fathoms. Blue mud. 

 Bottom temperature 37°'0 Fahr. ; surface temperature 82° - Fahr. 



Station 216. Midway between the Pelew Islands and New Guinea. Feburary 16, 

 1875. Lat. 2° 46' 0" N, long. 133° 58' 0" E. Depth 1675 fathoms. Globigerina ooze. 

 Bottom temperature 35°'4 Fahr. ; surface temperature 82°*8 Fahr. 



Station 198. In the Celebes Sea, between Celebes and Mindanao. October 20, 1874. 

 Lat. 2° 55' 0" N, long. 124° 53' 0" E. Depth 2150 fathoms. Blue mud. Bottom 

 temperature 38°'9 Fahr. ; surface temperature 85°"0 Fahr. 



Remarks. — Freyella echinata is readily distinguished from Freyella pennata by the 

 small papillate spinulation of the disk, and the spinelets sheathed with membrane crowded 

 with pedicellariae on the ovarial region. In Freyella. echinata the rays are somewhat 

 shorter in relation to the disk, but still more, delicate, and have a different character, the 

 lateral spinelets being longer and finer. In the armature of the adambulacral plates the 

 inner or furrow spine is always solitary, and the armature of the mouth-plates is in like 

 manner simpler. The madreporiform body is large and conspicuous, whereas in Freyella 

 pennata it is hidden. The pedicellariae are of larger size. 



4. Freyella fragilissima, n. sp. (PL CXIII. figs. 1-4). 



Bays eleven. R = 265 mm. ; r= 10 mm. B > 26 r. Breadth of a ray at the base, 

 5 mm. ; the greatest breadth of a normal ovarial inflation, 8-5 mm. (which is situated at 

 about 10 mm. from the disk); and the greatest breadth of the largest inflation, 16 "5 mm. 

 At 40 mm. beyond the disk the width of the ray is 4"25 mm. 



