EEPOKT ON THE ASTEUOIDEA. 37 



the plate are two or three small thornlets simulating more or less a continuation of the 

 furrow series. There may also be one or two on the aboral margin, and these are close to 

 the end next the furrow. 



The mouth-plates, which are large, broad, and convex, have a very echinulate character, 

 their surface being covered with numerous robust conical spinelets, sometimes forming two 

 or three more or less irregular series parallel to the median suture, but more frequently 

 without any definite order of arrangement. The marginal series consists of nine or ten 

 short, cylindrical, very slightly tapering spinelets on each plate, the two innermost on 

 each plate being equal and a little longer and more robust than the others, which are 

 fairly subequal until near the aboral end of the series. 



The actinal interradial areas are very small and with very few plates, probably not 

 more than eight or ten being present. The pair of intermediate plates adjacent to the 

 mouth-plates are much larger than any of the others, and are sbghtly tumid, which gives 

 them rather a characteristic appearance. All are covered with tolerably numerous short, 

 delicate, tapering spinelets. 



The anal aperture is subcentral and rather difficult to distinguish, and there is no 

 modification in the form or size of the surrounding paxillse as compared with the other 

 paxillse in that region of the disk. 



The madreporiform body, which is small, circular, and convex, is situated nearly, but 

 not quite, midway between the centre and the extreme margin, being a little nearer the 

 latter. Its surface is grooved with numerous rather coarse striations, which radiate cen- 

 trifugally. There is usually a large paxilla on the adcentral side of the madreporite, and 

 several other large paxilla? surround the margin. 



The papulae are confined to a comparatively large but elongate and pyriform area or 

 papularium at the base of the rays. In the largest example there are four rows of pores, 

 and the two inner ones are the longest and have larger pores, about nine in number in 

 each. In the two outer rows there are not more than four or five pores. The whole 

 number in a large papularium may thus be estimated at from twenty-five to thirty, and it 

 occupies an area ot about 6 mm. in length by 2 in breadth, or slightly more. In some 

 examples the papulae are all extended and appear to be of considerable length — measuring 

 2 to 3 mm. in a small specimen, and are delicate and tapering. 



Colour in alcohol, a bleached ashy grey, with a slight brownish shade over the paxillar 

 area of the disk. 



Individual Variation. — So far as I am able to judge from the small series of speci- 

 mens, the species appears to be remarkably constant in character, the only feature which 

 seems to show a little variability being the spinulation of the infero-marginal plates : the 

 spinelets below the lateral spine being more strongly developed in some cases than in others, 

 and in some there appear to be incipient traces of a tendency to form a median series of 

 spinelets larger than the rest, traversing the major dimension of the plate. 



