ASTEEOIDEA OE H.M.S. ' CHALLENaER ' EXPEDITION. 269 



suggestive o£ paxillgp, and most of the plates, excepting the inner 

 series, having a longer and more robust spiuelet springing from 

 the midst. 



Mouth-plates rather short and small, covered with numerous 

 closely-placed spinelets. A double line is present on the surface 

 of the plate, those near the median line of the mouth-angle being 

 largest, robust, compressed transversely, and Vith tips obtusely 

 rounded, and increase in length towards the inner extremity of 

 the plate. The innermost spines of the mouth-angle form a short 

 horizontal comb of four parallel spines directed towards the centre 

 of the mouth. The margins of the mouth-plates are fringed with 

 a line of about 8 small ciliary spines, which decrease in size and 

 robustness as they recede from the mouth. 



The paxillar area is extensiye over the disk, and contracts 

 rapidly along the rays, terminating in a point, in conformity with 

 the shape of the starfish. The paxillse are moderately large, with 

 a broad tabulum bearing in the centre one or occasionally two 

 isolated granules, and surrounded by 8 to 12 short claviform 

 spinelets around the margin which radiate outward slightly. 

 There is a little diminution in the size of the paxillse towards the 

 centre of the disk, but no trace occurs of any anal prominence 

 or peak whatever. The paxillse are arranged in very short 

 transverse rows at the sides of the rays, the irregular median 

 space being wide. The paxillsD become very small towards the 

 ends of the rays. 



The madreporiform body is small, slightly convex, with fine 

 striations, and is placed at about its own breadth distant from 

 the marginal plates. 



The ambulacral sucker-feet are pointed, and the extreme tip 

 appears to be very slightly thickened. 



The terminal (ocular) plate is elongate, and armed at the extre- 

 mity with four or five short robust spinelets directed outwards. 



Colour, in alcohol, brownish grey. 



Station. Off" Inaccessible Island, Tristan d'Acunha. Depth 

 90 fms. 



LINN. JOUEN. — ZOOLOGT, VOL. XYII. 20 



