108 THE VOYAGE OF H.M.S. CHALLENGER. 
The mouth-plates are large, elongately oval, and slightly convex actinally. Their 
armature consists of a marginal series of small spinelets, similar and equal in size to the 
adambulacral armature on the outer part, but longer, thicker, and conically-pointed at 
the inner extremity. On the actinal surface of the plate are two or three series of short, 
well spaced, papilliform granules, one of which is more or less definitely parallel to the 
median suture line, but the others show no definitely recular order. A few near the 
inner extremity of the plate are slightly larger than the others, and there is a general 
diminution in size towards the outer extremity of the mouth-plates. 
The actinal interradial areas are comparatively large, and form a triangular area 
extending as far as the fifth free adambulacral plate, and the sixth or seventh infero- 
marginal plate. They are occupied by small intermediate plates, which do not appear 
to present a specially definite order of arrangement so far as can be judged from the 
small groups of granuliform papillz or spinelets borne upon them, and these are well 
spaced. The majority of the plates bear a large pedicellarian apparatus composed of 
three or four enlarged papilla, which are very conspicuous in comparison with the small 
subequal granuliform papillz on the other plates. 
An anal aperture appears to be present in a subcentral position, but there is no modi- 
fication of the paxille in its neighbourhood. 
The madreporiform body, which is rather large and partially hidden by paxille, is 
situated near the margin and less than its own diameter distant from the supero-marginal 
plates. In the narrow intervening space most of the paxille form incipient pedicellarie, 
and are arranged in well spaced lineal series running from the madreporiform body to the 
margin, and consequently parallel to the median interradial line. 
Colour in alcohol, a slightly brownish white, with a bluish grey tinge over the disk, 
the latter probably owing to the thinness of the integument and the dark contents of the 
viscera. 
Localities.—Station 156. In the neighbourhood of the pack ice, near the Antarctic 
Circle. February 26, 1874. Lat. 62° 26’ 0” S., long. 95° 44’ 0” E. Depth 1975 
fathoms. Diatom ooze. Surface temperature 33°:0 Fahr. 
Station 157. South of Australia. March 3, 1874. Lat. 53° 55’ 0” §., long. 108° 
35’ 0” E. Depth 1950 fathoms. Diatom ooze. Bottom temperature 32°71 Fahr.; 
surface temperature 37°:2 Fahr. 
temarks.—This species is clearly very nearly related to Lonchotaster tartareus, from 
the deep water off the west coast of Africa. The example from Station 156, which has 
served as the type above described, appears to have been probably a young, or at any 
rate not a fully grown, specimen. After the foregoing description had been written, and 
the accompanying figures drawn on stone, I received two small specimens, which had 
been found amongst other material, from Station 157. They are slightly larger than the 
more southern example, but I place them with little hesitation in the same species. It is 
