382 THE VOYAGE OF H.M.S. CHALLENGER. 



and nearly to the tip in a thick fleshy mass. The tabulum or membranous base in which 

 the spinelets are imbedded stands raised and erect out of the general actinal membrane. 

 The groups are rather irregular in shape and the spinelets radiate slightly. The groups 

 are distinctly spaced, having clear channels between. 



The mouth-plates are rather large, and their armature consists of a marginal series of 

 five robust, thickly skin-covered spines on each plate, which increase slightly in size as 

 they proceed inward. The actinal surface of the united pair of mouth-plates is covered 

 with smooth, shining membrane ; and one or two short, robust, skin-covered spines stand 

 near the outer end of each plate. The trend of the mouth-spines is slightly downward, and 

 each mouth-angle has consequently rather a scoop-like appearance. 



The madreporiform body is large and situated about midway between the centre and 

 the margin, or rather nearer the former ; several larger spine-groups are amongst those 

 which surround it. The surface is flatly convex, the edge being bevelled. The striations 

 are fine and much convoluted, and on the dissepiments are developed numerous low 

 granuliform eminences. 



The anal aperture is subcentral, and there is no modification in the spine-groups 

 surrounding it. 



No pedicellarias are present. 



Colour in alcohol, a warm light brownish shade. 



Locality. — Station 313. Off Cape Virgins, eastern coast of South America, near the 

 Atlantic entrance to the Strait of Magellan. January 20, 1876. Lat. 52° 20' 0" S., long. 

 67° 39' 0" "W. Depth 55 fathoms. Sand. Bottom temperature, 47°'8 Fahr. ; surface 

 temperature, 48°"2 Fahr. 



Remarks. — This species is in some respects more nearly related to Cycethra electilis 

 than to the other forms. It is, however, at once distinguished by its generally inflated 

 character, by the elongate rounded rays, by the obscure marginal plates, by the small and 

 mass-like character of the spine-groups, and by the arrangement of the adambulacral 

 armature. 



Genus Ganeria, Gray. 

 Ganeria, Gray, Proc. Zool. Soc. Lond., 1847, Part xv. p. 83. 



This genus appears to have a remarkably restricted area of distribution, confined to 

 the neighbourhood of the Falkland Islands and the extreme southern point of America. 

 Although morphologically isolated, there seems to be little doubt about its being correctly 

 placed in the Asterinidse ; and I consider that its nearest ally is the genus Cycethra — 

 a form as yet only known from the southern point of America and the neighbourhood of 

 the Falkland Islands. Cycethra, however, extends to the Pacific side of the continent, 

 whereas Ganeria has been taken only in the Atlantic. 



