460 THE VOYAGE OE H.M.S. CHALLENGER. 



Localities. — "Porcupine" Expedition : 



Station 52, 1869. In the Faeroe Channel. Lat. 60° 25' N., long. 8° 10' W. Depth 

 384 fathoms. Bottom temperature — 0° - 8 C. ; surface temperature ll c, 2 C. 



Station 55, x 1869. In the Faeroe Channel. Lat. 60° 4' N., long. 6° 19' W. Depth 

 605 fathoms. Bottom temperature — l°-2 C. ; surface temperature 11°"4 C. 



2. Lophaster stettans, n. sp. (PL LXXI. figs. 4 and 5 ; PL LXXII. figs. 11 and 12). 



Rays five. R=32 mm.; r=ll mm. R<3 r. Breadth of a ray at the base, 12 

 to 13 mm. 



The rays are broad at the base, and taper gradually therefrom up to the extremity. 

 The abactinal surface is convex over the disk and upon the rays, and tapers regularly to 

 the extremity. The actinal surface is plane. The interbrachial arcs though wide are 

 angular ; and in consequence of the height and convexity of the disk, the declivity there 

 at the summit of the arc is rapid. 



The abactinal surface is beset with well-developed paxillaB, which are widely spaced 

 and arranged with more or less regularity in longitudinal lines along the rays. The 

 paxillge have a thick, robust, skin-covered pedicle, and are surmounted by a crown of 

 five to eight moderately robust subequal spinelets, with denticulate tips, usually shorter 

 than the pedicle, which radiate widely apart, and, when well preserved, have a strongly 

 marked stellate character ; whence the name of the species. Numerous papula? are 

 present in the interspaces, usually in groups of four or five, or more. 



The supero-marginal plates are well developed, and bear robust paxillae with long 

 pedicles, similar to those on the abactinal surface, excepting that the pedicles are longer 

 and thicker. The infero-marginal plates bear still larger paxillse, which are surmounted 

 by a crown of rather more numerous spinelets. The rotundity of the pedicle is main- 

 tained, and there is no modification in the form of the paxillag. The paxillse are well 

 spaced, and there are about eighteen between the median interradial line and the 

 extremity. 



The adambulacral plates are large, and are separated superficially by channels or 

 wrinkles in the membrane with which the whole actinal surface is invested, passing 

 obliquely from the furrow to the margin. Their armature consists of two series of spines. 

 (1.) A furrow series of rather large but delicate, tapering, skin-covered spines, which 

 radiate apart, and are partially united by web, forming a fan parallel to the furrow. 

 Near the mouth five spinelets are present in each comb, but the number is successively 

 reduced to four, three, and two, as they proceed along the ray, and probably only one 

 spine is preseut at the extremity. (2.) On the actinal surface of the plate is a lineal 

 transverse series of three (occasionally four near the mouth) large, robust, tapering, skin- 



1 This occurrence is recorded in Sir Wyville Thomson's Depths of the Sea, but I have not seen an example 

 from this station. 



