tJie EcMnodermata of the Arctic Expedition. 459 



Solaster furcifer , v. Diiben and Koren. 



Chcetaster borealiSf v. Diiben, Q2fv. Kougl. Vet.-AJkad, Forhandl. 1844, 



p. 113. 

 Solaster furcifer, v. Diiben & Koren, Kongl. Vet.-Akad. Handl. 1844, 



p. 243, t. Vi. f. 7-10. 



(^oU. Feilden : Cape Fraser, 80 fms. 



A starfish of somewhat depressed form, having five broad 

 flat ^rms. Proportion of disk-radius to length of arm 1 : 3. 

 The calcareous network of the dorsal surface is very regular ; 

 and the spine-clusters or paxillee, which spring from the inter- 

 sections, form longitudinal series which run parallel to the 

 median line of the ray ; consequently only two or three of the 

 middle series reach to the tip, although from fourteen to sixteen 

 may be counted at the base of the arm. The paxillte are 

 very compact and have a stout rounded base, nearly twice as 

 wide as high, bearing a crown of spinelets (about fifteen to 

 twenty) in length about equal to the diameter of the base. 

 The spinelets are, as a rule, flat ; and from the angles of the 

 apex, which is as broad as or broader than the base, proceed 

 two small denticles, giving the appearance to the spinelet of a 

 two-pronged fork ; sometimes the spinelet is triangular, in 

 which case there are tliree prongs. On the sides of the arms 

 are two rows of large paxill^e or spine-clusters, the lower 

 series being twice the breadth of the upper ones, and these 

 themselves being much larger than the rest of the dorsal 

 paxillaj just described. There are about twenty large mar- 

 ginal paxillffi from the arm-angle to the tip. Each interam- 

 bulacral plate bears three equal-sized spines, running parallel 

 to the furrow ; and exterior to these are three or four spines 

 webbed together into a " comb " and placed obliquely, or even 

 in some cases at right angles, to the ambulacral series ; 

 whilst midway between the combs and the margin of the 

 ray are three or four small spines (not sufficient to form a 

 paxilla proper), which stand quite isolated and only extend 

 about one third of the distance from the mouth to the tip of 

 the ray. The madreporiform tubercle is excentral and situated 

 at about one third the distance from the centre to the margin 

 of the disk. The mouth-plates are large and broad, the mar- 

 ginal spines interlocking with one another. 



Only two specimens were obtained by Captain Feilden, the 

 largest of which measures 65 millims. in its greatest diameter, 

 and 21 millims. across the disk ; the arms at the base are 

 13 millims. broad. 



