Report on the zoological collections made in the Indo-Pacific Ocean ...

ECHIJSrODERMATA, 129longer in the median line of each ray, where they form a remarkablyregular series, continued on to the disk, but they become more orless ill-delined on the raised portion ; the granules on the rest ofthe plates present no peculiarities, saving that they are a littlelonger on the sides of the raised portion of the disk. The respiratorypores on this surface are rather large, scattered, and simple.The supero-marginal plates are as much as 7 millim. high in thewidely open angle of the arms ; they are narrow, wider above thanbelow ; as these plates pass outwards they decrease in length andincrease in breadth ; they next decrease in size generally, andfinally they are again, though much smaller, of the same generalform as those of the angles of the arm ; the terminal three or fourtouch in the middle line : of these plates there are about 23 on.the side of each ray ; the condition of their armature is, perhaps,best described by saying that some of the granules elongate to formsmall spinous tubercles. The madreporic plate is situated aboutone third of the radius from the centre of the disk ; it is prominent,5'5 millim. long, and has the form of an irregular elongated oval.The infero-marginal plates are likewise about 23 in number, andtheir form in different regions presents very much the same variationsas those of the supero-marginal series ; the granules, however,do not present the same tendency to become spinous, though theyare all rather longer and not quite so closely packed. The adambulacralspines form a fringe of four flattened subequal spines, inaddition to which two smaller outer ones may be attached to thesame ossicle ; beyond these there are two or three much stouterspines, and beyond these again there may be two or three spines,the tips of which may be pointed. The granulation of the intermediateplates presents very much the same characters as that ofthe infero-marginal plates.This species may be distinguished from P. singularis or P. mUiarisby the length of its arms, and the shape and closer packing of theplates of the abactinal surface ; from the former it is also distinguishedby having the adambulacral spines shorter and blunter, though theyare by no means as blunt as in P. miUaris, where the adambulacralgroove is so wide.Colour : the specimen whose admeasurements have been given inthe above description is dark slate; another, in which 11 = 82 andr = 26, is light stone- coloured ; in it the disk is not elevated.Port Curtis, 5-11 fms. ; Prince of Wales Channel, 3-5 fms.18. Pentagonaster validus.This is a second new species which belongs to the Astrorjoniumdivision of the genus. The arms are distinct, rounded, and stout,the anus central and sometimes very distinct ; the granulation ofthe ossicles is rather coarse, and only a few larger granules arefound scattered over the abactinal surface ; there are three rows ofadambulacral spines.As five specimens of this form were collected we are able toK