REPORT ON THE ASTEROIDEA. 613 



on the ovarial region, of the narrowest and most attenuated description. It is further 

 characterised by the absence of tegumentary prickles in the abactinal membrane, by the 

 single small inner spinelet iu the armature of the adambulacral plates, and by the com- 

 paratively short lateral spines. 



7. Brisinga discincta, n. sp. (PI. CX. figs. 4-7). 



Disk and number of rays unknown. R=180 mm. Breadth of a ray at the base, 

 4 mm. ; across the middle part of the ovarial region, 3 '8 mm. (measured at 14 mm. from 

 the base); and at 100 mm. from the base, 2 - 75 mm. 



Rays elongate and tapering throughout from the base, no special ovarial inflation 

 perceptible ; subcylindrical and depressed at the base but still with a subtriangular 

 tendency ; at a short distance from the base the true subtriangular form is assumed, 

 the vertical height in proportion to the breadth being somewhat greater than usual, with 

 the converging slopes straighter and less incurved, and the median carination narrow 

 but sharply truncate. 



Two ray fragments, which measure 114 and 66 mm. respectively, I believe from their 

 width and general appearance to have both belonged to one ray ; even in this case the 

 terminal portion is still wanting to form an estimate of the full length. 



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

 brane ; at the base of the ray there are two or three transverse annular bands, none really 

 complete, of small narrow spicular plates, and rudiments of one or two still more incom- 

 plete, consisting of only one or two small plates at the margin of the ray. These are 

 the aborted representatives of the annular ridges in other forms, and no other spicules 

 are present in the membrane beyond this point in the species under notice. Tolerably 

 numerous small pedicellariaa are present upon the membrane along the ray, and were 

 probably disposed in transverse bands, this being distinctly the arrangement on the 

 proximal part of the ray. 



The ambulacral furrow is wide and measures 1'25 mm. at a part where the ray is 

 3 mm., about 40 to 50 mm. from the base. The adambulacral plates are fully twice as 

 long as broad, measuring 2 mm. at about 50 mm. from the base. Both the furrow-margin 

 and the outer margin are considerably incurved, and the ossicle is slightly flattened 

 actinally and has somewhat of a twisted appearance when viewed from above ; the adoral 

 end is convex, the aboral concave, and the plates overlap considerably. The adambulacral 

 armature consists of: — (1.) normally four small inner spinelets directed horizontally over 

 the furrow, though sometimes only three are present; (2.) a small actinal spine standing 

 perpendicularly on the actinal side of the plate; (3.) a long delicate lateral spine, articu- 

 lated on a small rudimentary infero-marginal plate, corresponding to every third adambu- 

 lacral plate, i.e. two unarmed adambulacral plates intervene between each successive lateral 

 spine. Of the small inner spines, two, which stand close together and often one rather 



