REPORT ON THE ASTEROIDEA. 491 



smaller and rather wider apart ; indeed, in some specimens one is almost inclined to class 

 them along with the secondary series. Midway on the horizontal margin of the flange is 

 one small pointed mouth-spine ; and in a large specimen a second and rather larger spinelet 

 occurs between this and the innermost mouth-spine, and nearer to the latter. 



The actino-lateral spines are rather robust, well spaced, tapering slightly at the 

 tips, excepting those spines included within the interradial area, which are slightly 

 thickened, and do not meet their corresponding spines from the neighbouring ray in the 

 median interradial Hue. There are twenty-five to twenty-seven actino-lateral spines on 

 each side of a furrow, the seventh or eighth from the mouth being longest ; after this they 

 gradually diminish in size as they proceed outward, maintaining, however, a fair length 

 even at the extremity, where they are a little shorter than the first (or adoral) spine of 

 the series, thus forming a conspicuous little fringe round the extremity of the ray. The 

 ambulacral furrow is extended vertically up the extreme tip of the ray, but is not exposed 

 on the abactinal surface, being arched over by the terminal spinelets just described. 

 Immediately inside this ocular fringe on the abactinal surface is a little ridge of eight 

 to ten minute conical spinelets or papillae, which forms a semi-circular collaret at the 

 extreme tip. 



The actinal membrane is as transparent as the abactinal membrane, the actino-lateral 

 spinelets formiug the floor of the test and projecting only their pointed tips beyond the 

 sharp margin, to which they impart a delicate serrate character. 



Colour in alcohol, a lisrht straw colour vero-inp- towards golden brown. 



Locality. — Station 122-1 22c. Off the coast of Brazil, south-east of Pernambuco. 

 September 10, 1873. Lat. 9° 5' 0" S. to 9° 10' 0" S., long. 34° 49' 0" W. to 34° 53' 0" W. 

 Depths 32, 120, 350, 400 fathoms. Eed mud. Surface temperature 77°*5 Fahr. 



Unfortunately only the Station number is indicated on the label accompanying these 

 specimens, and no record is given as to the particular dredging in which they were 

 obtained. 1 



Genus Hymenaster, Wyville Thomson. 



Hymenaster, Wyville Thomson, The Depths of the Sea, London, 1873, p. 120. 



This genus was established by Sir Wyville Thomson for the reception of a remark- 

 able Asterid discovered during the cruise of H.M.S. "Porcupine." Only a single example 

 was obtained, and, although the form was not fully described, the characters which 

 distinguish it from Ptcraster were duly recognised and a good figure of the actinal aspect 

 of the starfish was given by Sir Wyville Thomson. Some doubts were subsequently 

 expressed by Perrier 2 as to the validity of separating Hymenaster from Pteraster, but 



1 From an examination of our Station notes I have no doubt the specimens came from the trawling in 350 

 fathoms. — Ed. 



2 Nouu. Archives Mas. Hist. Nat. 1878, 2e Serie, t. i. p. 55. ' 



