KEPOET ON THE ASTEROIDEA. 641 



9. Freyclla benthophila, n. sp. (PI. CXI. figs. 5-8). 



Rays six. E = 88 mm. ; r = 3 mm. R = 30 r, approximately. Breadth of a ray 

 at the base, 2 - 5 mm. ; at 10 mm. from the disk, 175 mm. ; and at about midway between 

 the base and the extremity, 1 mm. 



Rays very long, extremely delicate and attenuate, cylindrical at the base, very slightly 

 inflated in the ovarial regions, which extend about 10 mm. from the disk, or occupy the 

 proximal ninth of the ray; beyond this the ray is subtriangular with a truncate carination, 

 and tapers continuously to a very attenuate extremity. The interbrachial arcs, though 

 sharply rounded, have somewhat of an angular character. 



The disk is small, with the abactinal surface slightly subconically convex, and higher 

 than the abactinal surface of the rays, the outline when seen in profile passing with a 

 gentle slope towards and along the ray, the interference of the ovarial inflation being very 

 slight. The abactinal area of the disk and of the ovarial regions is covered with very 

 delicate calcareous plates overlaid with extremely delicate membrane. The plates bear 

 two or three short, rather stumpy but very minute, spinelets (quite microscopic), and a 

 number of small distributed pedicellariae, the whole having more or less of a grouped 

 appearance on each plate. On the outer part of the ovarial regions the microscopic 

 spinelets frequently appear to be less numerous. The plating does not extend beyond 

 the ovarial region, and from thence to the extremity the abactinal surface of the ray is 

 covered with an extremely delicate semitransparent membrane. Small pedicellariae are 

 distributed over the membrane and, though numerous, have a comparatively widely spaced 

 appearance ; they are most numerous towards the lateral margin, and may to a certain 

 extent be said to occur in patches corresponding to the " vertebra? " of the ray, but do not 

 approach the character of the aggregated groups on the saddle-like sacculi noticed in 

 other species. 



The ambulacral furrow is broad and occupies nearly the whole of the actinal surface 

 of the ray, the adambulacral plates forming only a narrow margin ; its width is about 

 1 mm. where the ray is 175 mm. The adambulacral plates are elongate, 1*3 mm. in length 

 at 10 to 12 mm. from the disk, and measure the same quite close to the extremity, where 

 the length appears relatively greatly emphasised in consequence of their narrowness and 

 attenuation. The plates are very narrow midway between their extremities, their outline 

 being distinctly concave ; the furrow-margin is the most incurved, and the outline of 

 the furrow has consequently the appearance of a lineal series of confluent ovals. The 

 armature of the adambulacral plates consists of a single very delicate spine articulated on 

 a small tubercular prominence on the middle of the actinal surface midway between the 

 •extremities, and an equally delicate lateral spine, often of the same length but normally 

 slightly longer, articulated on a rudimentary infero-marginal plate ankylosed on the lateral 

 wall immediately beneath the spine just mentioned, usually on alternate plates, but some- 

 times less frequently. These spines are enclosed in delicate membranous sheaths with 



(ZOOL. CHALL. EXP. PART LI. 1888.) 81 



