REPORT ON THE ASTEROIDEA. 313 



This is as follows : On the lateral margins of the plates, i.e., at right angles to the furrow- 

 are a series of spiuelets which have the appearance of being in direct continuation of the 

 furrow series above described ; they are not compressed, however, but papilliform, and they 

 decrease in size as they recede from the furrow. A few similar papilliform spinelets pro- 

 ceed along the outer extremity and thus complete a series surrounding the whole margin 

 of the plate. Those on the lateral margins are slightly inclined over the rather wide 

 furrow that separates adjacent plates towards the corresponding series of spinelets on the 

 next plate. The adambulacral plates being very broad on the inner part of the furrow 

 there are about seventeen or eighteen spinelets on the lateral and furrow margins there ; 

 the proportion of breadth decreases as the plates proceed along the ray and the number of 

 spinelets is consequently less, being about thirteen or fourteen near the middle of the ray. 

 The adambulacral plates on the inner part of the ray have a single lineal series of four or 

 five small spinelets standing on the median line of their area, parallel to the lateral margins, 

 and consequently obliquely transverse to the furrow. Further out additional spinelets 

 occur on the outer part of the plate, and there is a tendency to form two converging series, 

 the point of the wedge being towards the furrow. One of the spines near the outer end of 

 the plate is longer than the rest, very delicate, tapering, and sharply pointed. This minute 

 spinelet is continuous throughout the series, excepting the innermost three plates and at 

 the extreme tip. 



The actinal interradial areas are very small and triangular in outline. They are 

 occupied by a comparatively small number of rather small plates, the margins of which 

 are beset with moderately elongate papillae, with one or more in the centre ; all the spinelets 

 are of equal length, rather wide apart, and stand nearly vertical, which gives the plates 

 a somewhat paxilliform character, though the armature would be more correctly described 

 as forming a rather widely spaced group. 



The mouth-plates are small and elongate, with nine or ten spinelets on the free margin; 

 the outermost three or four of this series are compressed and truncate, the rest cylindrical, 

 tapering, and sharply pointed, and the innermost are the longest. A lineal series of about 

 eleven small spinelets runs parallel to the median suture, the innermost nearly as long as 

 the marginal series, whilst the outermost are merely papilliform granules. On the margin 

 adjacent to the adambulacral plate is a series of five or six spines, which rapidly diminish 

 in size as they proceed outward, and do not always extend as far as the median series above 

 mentioned. At the widest part of the plate there is an intermediate series of about four 

 spines midway between the outer series of spines and that adjacent to the median suture, 

 and parallel to the latter. 



The well-defined pentagonal area of the abactinal paxillse is slightly inflated, especially 

 in the radial regions, the character being there emphasised by a slightly depressed central 

 area, from which shallow channeblike continuations extend along the interradial lines, but 

 die out before reaching the maro-in. 



(ZOOL. CHALL. ESP. — PAKT LI. 1888.) 40 



