KEPOET ON THE ASTEROIDEA. 107 



thick and obtusely rounded, and they are usually grouped close together in consequence 

 of the crowding of the paxUlse. A number of the paxillse have two or four enlarged 

 papillae, which form incipient pedicellariffl. The paxillae present no definite order of 

 arrangement. 



The marginal plates are small and short ; the plates of the superior series are the 

 smallest, and are inconspicuous, being much less in height than those of the companion 

 inferior series. The supero-marginal plates are thirty in number counting from the 

 median interradial line to the extremity, and are rectangular with the height about equal 

 to the length throughout. They are covered with short, uniform, equal, papilliform 

 spinelets, similar to, but slightly longer than, those on the paxillse, and are devoid of 

 any large or true spines whatever. The position of the supero-marginal plates is entirely 



marginal. 



The infero-marginal plates correspond exactly in length to the superior series, but 

 their height or transverse dimension is much greater, being from twice to three times as 

 great in the interbrachial arc, but diminishing along the ray until at the extremity 

 the height and length are subequal. Their posture is such as to form a broad marginal 

 border to the actinal area of the disk and along the inner half of the ray, the breadth 

 diminishing towards the extremity, where they conform to the rounding of the ray, and 

 only a small part is visible in the actinal view. Their surface is covered with short, 

 robust, papilliform spinelets, subconically pointed. The transverse furrows between 

 adjacent plates are well defined. Normally every plate in the interbrachial arc, and as 

 far as midway along the ray, bears at its end, adjacent to the supero-marginal plate, 

 a pedicellarian apparatus, formed by two to four thickened and enlarged papilliform 

 spinelets, and larger than those constituting the general covering of the plate. This 

 pedicellarian apparatus is consequently a conspicuous object, and there are no larger 

 spines on the plate. 



The adambulacral plates are longer than broad (in fact remarkably large for so small 

 a form), and they have a slightly convex margin towards the furrow. Their armature 

 consists of a furrow series of seven or eight short, subclavate, papilliform spinelets, sub- 

 equal in length on the outer half of the ray, but with the median ones slightly longer on 

 the inner part of the ray ; these are directed over the furrow, radiating slightly apart. 

 External to the furrow series, and on the actinal surface of the plate, is a longitudinal 

 series of five or six short, equal, papilliform granules (scarcely worthy of being called 

 spinelets) ; and again external to this are one or two subparallel, but often irregular, longi- 

 tudinal series of similar and equal-sized papilliform granules or spinelets, the number in 

 these outer series being smaller in consequence of the presence of a large pedicellarian 

 apparatus composed of three or four (usually four) considerably enlarged papilliform 

 spinelets, placed near the aboral margin of the plate, and preventing the extension of the 

 one or two outer series of papilliform granules there. 



