108 



THE VOYAGE OF H.M.S. CHALLENGER. 



The mouth-plates are large, elongately oval, and slightly convex actiually. Their 

 armature consists of a marginal series of small spinelets, similar and equal iu 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 regular 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 papillte 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 papillae, which are very conspicuous in comparison with the small 

 subequal granuliform papillae on the other plates. 



An anal aperture appears to be present in a subcentral position, but there is no modi- 

 fication of the paxillae in its neighbourhood. 



The madreporiform body, which is rather large and partially hidden by paxillae, 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 paxillae form incipient pedicellariae, 

 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° - Fahr. 



Station 157. South of Australia. March 3, 1S74. Lat. 53° 55' 0" S., long. 108° 

 35' 0" E. Depth 1950 fathoms. Diatom ooze. Bottom temperature 32 0- l Fahr. ; 

 surface temperature 37° "2 Fahr. 



Remarks. — 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 



