194 ME. W. PEECT SLADEN OF THE 



The crowns are closely placed, the interspaces rather deep ; and 

 the stars often appear to overlap. A more or less distinct lineal 

 arrangement o£ this ornamentation may be observed upon the 

 rays, although here and there irregular paxillse-crowns, with fewer 

 or more minute spinelets as the case may be, are interspersed. 

 The " stars " diminish in size as they proceed outward on the my. 

 Spiracula small and rather widely spaced. Oscular orifice small ; 

 spinelets of the valves short and crowded. 



Ambulacral furrows narrow, straight, not petaloid, converging 

 gradually towards the extremity. Suckers arranged in simple pairs. 

 The borders formed by the transverse combs of ambulacral spine- 

 lets rather broad. Each comb with 5 spinelets, comparatively 

 short, the innermost one diminutive, not half the length of the 

 others, and placed aboral to them on the plate, the comb being 

 thus curved round aborally at the margin of the furrow ; the 

 spine next to the outermost is usually the longest. Web mode- 

 rately thick and semitransparent, rather deeply incurved between 

 the spinelets, somewhat thickened round them, and slightly sac- 

 culate over their extremities ; continued from the outermost spine 

 of the comb far out on the actino-lateral spines. 



Segmental apertures rather large and conspicuous for this 

 genus. The papilla is comparatively large, and free on its aboral 

 side only, forming a regular semicircular lip, the remainder of the 

 papilla being entirely hidden in membrane. 



Mouth-plates short, but widely expanded laterally, rising by a 

 gradual slope into a high and angular median keel, and forming a 

 prominent peak aborally. Each plate bears one moderately robust 

 secondary sujDcrficial spine placed rather nearer the anterior 

 margin of the plate than the middle. These spines are shorter 

 than the mouth-spines proper, and are covered with a thick in- 

 vesting-membrane slightly sacculate at the extremity. Five 

 mouth-spines are situated on the horizontal margin of each plate, 

 the innermost the longest, the next slightly smaller, and the outer 

 three much smaller. Each of the spines is covered with a mode- 

 rately thick subsacculate investing membrane ; and no web is de- 

 veloped, except in one single abnornal instance, where a secondary 

 spine is united with the inner or first mouth-spine proper. 



The first or most adoral transverse ambulacral combs of two 

 neighbouring rays touch one another at their bases behind the 

 aboral peak of the mouth-plates, but are not joined together. 



The actino-lateral spines are long, delicate, closely placed, and 





