REPORT ON THE ASTEROIDEA. C31 



tube-feet. It would seem probable that the function of the numerous pedicellarise on the 

 sacculi of these spinelets was mainly, if not wholly, that of keeping the tube-feet clean. 

 The actinal spinelet is about 5 mm. in length at 60 mm. from the disk, and is articulated 

 on a robust tubercle, which occupies most of the actinal surface of the plate between the 

 middle and the adoral end. It is encased in a delicate membranous sheath, crowded with 

 very small pedicellarias. The lateral spines are not remarkable for their length, being 

 about 9 to 10 mm. at 70 to 80 mm. from the disk ; they are articulated on a tubercle-like 

 rudimentary infero-niarginal plate ankylosed on the lateral margin of the adambulacral 

 plate, in a line with the tubercle on the actinal surface, and are rather robust at the 

 base, but taper to a fine extremity, and they are encased in a delicate membranous sheath 

 crowded with small pedicellarise. 



The actinostome is of great width, its diameter being 13 mm. in a disk measuring 23 

 mm. The buccal membrane is thick and opaque, and the margin of the mouth is beset 

 with a closely crowded villous fimbriation (? probably an exposure of the internal surface). 

 The mouth-plates are small and inconspicuous, somewhat in the form of a truncate wedge, 

 the adoral margin of the pair presenting only a slightly convex margin. Each plate bears 

 two small mouth-spines about 1 mm. in length ; the inner pair are a little removed from 

 the median line of juncture, and are directed horizontally over the buccal membrane, 

 usually parallel to one another, or only slightly divergent ; the second pair are at the 

 extreme edge of the adoral margin of the plates, i.e., one spine on each plate, and are 

 directed horizontally at a right angle to the median interradial line, and iu such a manner 

 that with the corresponding spine of the neighbouring mouth-angle a bar is formed across 

 the ambulacral furrow at the margin of the actinostome. Both the mouth-spines are 

 encased in a delicate membranous sheath, that of the inner pair being wide and bag-like, 

 usually expanded at the tip and pyriform, and numerous small pedicellariae are borne 

 upon the membrane. The outer pair of spinelets which cross the furrow have the appear- 

 ance of being imbedded in the actinostomial membrane, and their presence is only detected 

 by the pedicellarioe. A robust secondary mouth-spine is placed well back on the actinal 

 surface of each plate, articulated on a tubercular eminence, and encased in a rather wide, 

 delicate, membranous sheath crowded with pediceUarise. 



The madreporiform body is small, about 2*5 mm. in diameter, convex, subtubercular, 

 and situated quite at the margin of the abactinal surface of the disk, at the summit of one 

 of the cleft -like interbrachial arcs, its position in relation to the plane of the abactinal 

 surface being slightly oblique. Its surface is marked with a few highly convoluted 

 striation-furrows, and the margin is surrounded by an indistinct circlet of the abactinal 

 tegumentary spinelets. A very distinct anal aperture is present ; it is exceutric in position, 

 and the margin is surrounded with rather larger spinelets than elsewhere upon the disk, and 

 a, retracted tubular structure with punctured extremity may be seen within its periphery. 



Colour in alcohol, a bleached yellowish white. 



