REPORT ON THE ASTEROIDEA. 85 



The adambulacral plates form a straight or very faintly festooned margin to the furrow. 

 Their armature consists of — (1.) A furrow series of nine or ten rather elongate spinelets, 

 which are slightly compressed, not tapering, and with rounded extremities. The middle 

 spines are largest, and those at the end of the series diminish by gradation, the outermost 

 being small and s'etiform. The spinelets form straight series, and stand almost parallel 

 to one another, radiating very slightly. (2.) On the actinal surface of the plate, behind 

 the furrow series, stands a single large, conical, sharply pointed spinelet, nearly as laro-e and 

 robust as the lateral spines. There are a few minute setiform spinelets irregularly disposed 

 on the actinal surface of the plate on each side of the large spine and along the outer 

 margin of the plate. 



The mouth-plates are large, and the united pair are prominently convex actinally, form- 

 ing a rather low but well-defined elliptical-shaped tumidity. Their armature consists of a 

 marginal series of ten to twelve short mouth-spines on each plate. These increase slightly 

 in length as they proceed inwards, and the longest are not greater than the largest spines 

 in the furrow series of the adambulacral plates. The actinal surface of the plate is covered 

 with numerous short, papilliform spinelets, which increase in size and robustness at the 

 inner end of the plates, those at the extremity being quite equal in length to the mar- 

 ginal series and even slightly more robust. These larger spinelets are crowded at the 

 extremity. There is no representative on the mouth-plates of the large isolated secondary 

 spine on the actinal surface of the adambulacral plates. 



The actinal interradial areas are large. The intermediate or ventral plates, which 

 are small, numerous, and regularly quadrate, are arranged in lineal series or columns 

 extending from the adambulacral plates to the marginal plates — the breadth of the 

 columns at their inner extremity corresponding to the length of the adambulacral plates, 

 but contracting as they proceed outward, in consequence of the diminution of the size of the 

 plates. The intermediate plates are covered with papilliform granules or spinelets, and 

 each of those in the area of the disk bears a single, moderately robust, conical pointed 

 spinelet, springing from the midst. 



The anal aperture is subcentral and distinct. 



The madreporiform body is obscured by paxilhe, and these being more widely spaced 

 in its vicinity indicate the position of the body, which is rather nearer the margin than 

 midway between the centre and the margin. 



The terminal (ocular) plate is minute. 



The tube-feet are conical, with a very minute, conical, mamelon-like termination, and 

 there is no sucker-disk. 



Colour in alcohol, a bleached ashy-grey, and often with a more or less ochraceous 

 shade on the actinal interradial areas. 



Young Phase. — In its early stages this species has a very different appearance from 

 that presented by the adult, the rays being short and triangular, and the marginal con- 



