REPORT ON THE ASTEROIDEA. 259 



On the outer part of the ray the spinelets on the centre of the tabulum become longer 

 and more spiniform. 



The infero-nmrginal plates are confined entirely to the actinal surface of the ray, and 

 have a well-defiued median keel. Each plate bears only one true spine, the lateral, placed 

 at the outer extremity of the plate ; it is short, thin, compressed and lancet-formed, the 

 longest measuring about 15 mm. On the ridge are normally five equal-sized squamiform 

 spinelets, about one-third the length of the lateral spine, compressed, tapering, some- 

 times pointed, but often obtusely rounded at the tip. These have the same direction in 

 relation to the plate as the lateral spine, and consequently pass slightly over the aboral 

 margin of the plate. A second series of smaller spinelets stauds on the inner side of the 

 series just described, and is usually directed along the median line of the plate ; but this 

 series is subject to much irregularity in the size, posture, and number of the spines, having 

 sometimes one or more spinelets as large as the aboral series, sometimes directed towards 

 one margin and sometimes towards the other. The margins of the keel are fringed with 

 delicate cilia-like spinelets, those on the inner part of the plate having a thick and 

 saccular investment, which gives them a robust papilliform appearance in comparison to 

 the others. 



The adambulacral plates carry an armature arranged in the following manner : — (1.) A 

 single furrow spine, curved scimitar-like, delicate, compressed, obtuse at the tip. (2.) 

 Immediately behind the furrow spine, a single spine slightly longer, more robust, slightly 

 compressed or triangular, tapering, pointed, and slightly geniculate, the curvature being- 

 much less than that of the inner spine. (3.) Behind the foregoing stand either two straight 

 spines side by side, or a spine and a pedicellaria of equal length and in the same relative 

 positions. These are rather shorter than the second single spine above noticed ; the spine 

 is moderately robust, tapering, and pointed ; and the pedicellaria has long delicate 

 jaws, equal in length to the accompanying spinelet. The pedicellaria is usually on the 

 adoral side, but not invariably. On a few of the plates on the inner part of the ray a 

 second pair of spines may be present, but usually the outer part of the plate bears only 

 two or three ciliary spinelets rather thickly invested. 



The mouth -plates are prominent and extend far upward into the actinostome ; each 

 plate usually (in one example always) bears a single very large pedicellaria at its inner- 

 most point. The marginal and actinal or superficial spines are subequal in size ; the 

 former somewhat irregular in position, the latter in a series parallel to the median suture. 

 The mouth-armature is difficult to formulate in the type specimen without preparation. 



The actinal interradial areas are very small, and include only a pair of small inter- 

 mediate plates, each of which bears one large pedicellaria, but shorter than those on the 

 adambulacral plates and with more obtuse jaws. At the base of the pedicellaria are a few 

 minute cilia-like spinelets. A small intermediate plate separates the infer o- marginal plate 

 from the adambulacral platt' throughout the ray. A few of these plates on the inner- 



