REPORT ON THE ASTEROIDEA. 505 



or pad is developed on the surface that fits over the aperture, upon which it closes like 

 a valve. 



The mouth-plates are of moderate size ; widely expanded laterally, the keel along the 

 junction being well developed, prominent aborally, and with a rather produced peak 

 adorally. Two secondary or superficial spines are present on each plate — one near the 

 adoral extremity, the other shorter and more robust, midway on the plate and with a 

 wide-flaring investment. It is a question whether the anterior pair ought not, from 

 their position, to be ranked with the true mouth-spines. Mouth-spines proper three or 

 four in number, acicular, and placed on the margin of the lateral flange. 



The actino-lateral spines are closely placed, and entirely hidden in the thick fleshy 

 membrane with which the actinal interradial areas are uniformly covered ; fifty to sixty 

 spiuelets are present on each side of the ray. 



Colour in alcohol, purplish grey on the abactinal surface, pinkish purple on the actinal 

 surface. 



Locality. — Station 295. Off the west coast of South America. November 5, 1875. 

 Lat. 38° 7' 0" S., long. 94° 4' 0" W. Depth 1500 fathoms. Globigerina ooze. Bottom 

 temperature 35°'3 Fahr. ; surface temperature 58°'5 Fahr. 



Remarks. — This is a large form, approaching Hymenaster nobilis in size, which it also 

 resembles in its fleshy habit. In Hymenaster carnosus, however, the paxillee-crowns do 

 not form definite areas, and the spiuelets are large and spike-like ; the spiracula are very 

 minute and arranged in groups ; and there are two spinelets in the adambulacral 

 armature. 



7. Hymenaster glaucus, Sladen (PL LXXXIV. figs. 1 and 2 ; PL LXXXVI. figs. 4-6). 



Hymenaster glaucus, Sladen, 1882, Journ. Linn. Soc. Lond. (Zool.), vol. xvi. p. 221. 



Marginal contour stellato-pentagonal. Interbrachial arcs well indented, forming a 

 distinct angle, except in very large specimens, where the web has become somewhat 

 overgrown, and abnormally thickened. Minor radial proportion from 68 to 76 per 

 cent. R = 46 mm.; r = 35 mm. The rays taper to a fine extremity and the web is 

 rather full on the margins, and somewhat irregular in consequence. General form very 

 depressed. On the abactinal surface the radial areas are well marked out, distinct from 

 the fringe and interradial membrane, by a regular linear arrangement of paxillse-spine- 

 lets, the radial areas being elevated above the general surface. The pseudo-sides of the 

 rays are short and perpendicular ; the rays themselves having the appearance of standing 

 in relief above the superficies of the marginal and interradial webs, tapering to a fine 

 point, and maintaining their distinctness up to the very extremity. The lateral web or 

 fringe is largely developed, and, being rather full, is in consequence somewhat irregular. 



The supradorsal membrane is furnished with very numerous muscular fibres, which 



(zool. CHALL. ESP. — PART LI. — 1888.) 64 



