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 
spinelets 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.—Vhis is a large form, approaching [ymenaster 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 spinelets 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 (P]. 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 ares 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 paxilla-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. EXP.—PART LI.—1888.) 64 
