ASTEEOIDEA OF H.M.S. CHALLEI^GEE, ' EXPEDITION. 195 



extend to the margin of the actinal s^urface ; the welj I'aintly 

 rounded over their extremities and slightly festooned betwceu. 

 The spines are horizontal in their disposition, forming a flat ven- 

 tral surface to the disk ; and the fringe extends very slightly 

 beyond the margin ; and the spines diminish to quite microscopic 

 proportions at the extremities of the ray. 



Colour, in alcohol : — The actino -lateral spines, the ambulacral 

 spines, the mouth-plates, and the moutli- spines are all of a deli- 

 cate rosy-pinii colour ; and this, seen through the semitransparent 

 light-flesh-coloured investing tissue, gives an exquisitely beautiful 

 appearance to the underside of the Starfish. The general colour 

 of the dorsal area is a pinkish white, verging on flesh-colour. 



Station 311. Lat. 52° 50' S., long. 73'' 53' W. Depth 245 fms. ; 

 bottom temperature 7°'7 C. ; mud. 



Pteeastek semieeticulatus, u. sp. 



Marginal contour substellate ; interradial angles well indented, 

 the minor radial proportion being 57 per cent.; jR=14 millim., 

 r=8 millim. The sides of the rays slightly and gracefully curved 

 outwards, the tips naturally upturned and incised, bringing the 

 extremity of the ambulacral furrow on to the dorsal area. Dorsal 

 profile rather high and bombous over the disk, tapering ofi" rather 

 steeply to the extremity of the rays. Actinal surface slightly 

 concave. 



Supradorsal membrane marked out with conspicuous reticu- 

 lated lines of membrane, although no regular divisional fibres or 

 independent tendinous network can be made out — the fibres 

 present being fine, and only distinguishable when highly mag- 

 ]iified. Paxillse moderately long, with the spinelets radiating 

 Avell outwards, about G to 8 or even more in number ; the 

 corrugated membrane which they support lying thick and baggy 

 over their tips, and forming the regular lines and cross lines 

 whereby the character above noted is produced. None of the 

 spinelets are more prominent than the rest ; and although a 

 central one appears to be normally present in the centre of the 

 mesh, this is very frequently absent towards the end of the rays. 

 The membrane is semitransparent, and contains no spicules ; 6 to 

 10 large-sized, irregularly disposed spiracula occur in each mesh- 

 like area 



Ambulacral furrows moderately wideband sublanceolate ; the 

 Bucker-feet more or less alternate, and shov.iug distinctly a ten- 



