REPORT ON THE ASTEROIDEA. 599 



mm. from the base. Beyond this the ray has a flattened or snbdepressed appearance, the 

 abactinal surface being convex, with a broad and somewhat indistinct median carination, 

 the breadth being greater than the height. 



The disk is small and button-like in form, the abactinal surface being convex, flattened 

 centrally, and gradually rounded at the margin down to the base of the rays. The abac- 

 tinal surface is beset with robust imbricating plates, between which are interspaces punc- 

 tured by two or three papulse. The plates are irregularly convex abactinally, and each 

 bears two or three short, moderately robust, tapering, pointed spinelets about 2 mm. in 

 length, which are near together at their bases, but radiate slightly apart, giving a decidedly 

 echinulate appearance to the abactinal surface. The spinelets appear to be naked, and I 

 have detected no pedicellarias upon the disk. The papula? are delicate, elongate, and 

 vermiform. The ovarial region at the base of the rays is covered with a thick coriaceous 

 skin, underlaid with small imbricating calcareous plates and punctured by numerous 

 widely spaced, generally distributed papulse. The outer half, or even outer two-thirds, of 

 the ovarial region is traversed by bands of small prominent imbricating plates, which 

 bear isolated, robust, conical spinelets 2 to 3 mm. in length. The bands are about 5 mm. 

 apart, and the ovarial region has consequently the appearance of being encompassed by 

 five or six echinulate rings ; on the actinal surface of the inner third of the ovarial region 

 the plating is more compact and irregular, and the spinelets are irregularly distributed, 

 but do not occur on the lateral wall of the ray. On some of these spines are traces of a 

 membranous sheath with closely crowded small pedicellarise. The membrane between 

 the echinulate rings is perfectly smooth and bears no pedicellarise or tegumentary spinelets. 

 Beyond the ovarial region the abactinal surface of the ray is covered with a thin semi- 

 transparent membrane, and the transverse rings are represented only by short lateral 

 calcareous ridges, the component plates appearing to be more or less ankylosed, upon 

 which are borne from four to six rather long spinelets invested with thick membranous 

 sheaths, crowded with numerous microscopic pedicellarise. The spinelets in the middle of 

 a series are generally slightly longer than the others, and may measure from 6 to 8 mm. 

 in length ; the uppermost spinelet is generally much less, and the smallest of the series. 

 The lowest spinelet springs from a plate abutting on the adambulacral plates, and is the 

 representative of the lateral or infero-marginal spine. It may measure 7 mm. in length, 

 but is often less. The delicate membrane which covers the abactinal surface of the ray 

 bears small round or irregular patches or sacculi crowded with microscopic pedicellariae, 

 the patches, though isolated, being numerous and quite irregular in their disposition. 

 There is no tendency whatever towards the formation of the elongate, saddle-like, saccular 

 bands which occur in Brisinga generally. 



The ambulacral furrow is wide, measuring about 4 mm. at a part where the breadth 

 of the ray is 8 mm. The adambulacral plates, which form a narrow well-rounded margin 

 to the furrow, are very short, only about 1 mm. in length, distinctly but not widely 



