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



sunken, of irregular rhomboidal shape, with corners rounded ; length to breadth 17 : 1*3. 

 Central primary plate smaller than the others, circular, sunken, separated by a double 

 row of small circular scales from five large sunken, nearly round plates which surround 

 it ; the rest of the upper surface is covered with small rounded scales, with a larger one 

 on the margin. Under surface covered with small rounded plates, irregularly disposed ; 

 genital scales long and very narrow, on the free edge of which are fine, short, square 

 papilla?, corresponding to similar ones on the side arm plates. One small rounded 

 tentacle scale, situated near inner angle of plate. Three or four minute, slender, 

 rounded arm spines standing low down on arm plate ; upper one longest. Colour 

 in alcohol, straw. 



Station 323.— February 28, 1876 ; Lit. 35° 39' S, long. 50° 47' W. ; 1900 fathoms; 

 grey mud. 



Ophiomusium lymani, Wyv. Thorn. 



Ophiomusium Lymani, Wyv. Thoiu., Depths of the Sea, p. 172, figs. 32, 33, 1873; Lyra., Bull. 

 Mus. Comp. Zool., vol. v., part 7, p. 113. 



The specimens from the following widely separated stations showed certain minor 

 differences. For example, those from Station 235 had more arm spines and rather more 

 numerous lower disk plates, and the tentacle scales were entire, instead of divided. I 

 have deemed it best to keep the varieties together for the present. 



Station 45.— May 3, 1873; lat. 38° 34' N., long. 72° 10' W. ; 1240 fathoms; mud. 

 Station 50.— May 21, 1873; lat. 42° 8' N., long. 63° 39' W. ; 1250 fathoms; grey 

 ooze. Station 76.— July 3, 1873; lat. 38° 11' N., long. 27° 9' W. ; 900 fathoms; 

 globigerina ooze. Off Tristan d'Acunha ; 1100 fathoms. Station 169. — July 10, 1874 ; 

 lat. 37° 34' S., long. 179° 22' E. ; 700 fathoms; grey ooze. Station 191.— September 

 23, 1874; lat. 5° 41' S., long. 134° 4' E. ; 800 fathoms; mud. Station 235.— 

 June 4, 1875; lat. 34° 7' N., long. 138° 0' E. ; 565 fathoms; mud. Station 296. 

 —November 9, 1875; lat, 38° 6' S., long. 88° 2' W. ; 1825 fathoms (only arms); 

 red clay. 



Ophiomusium laqueatum, Lym. (PL II. figs. 10-12). 



Ophiomusium laqueatum, Lym., Bull. Mus. Comp. Zool, vol. v., part 7, p. 113, pi i. 14-16, 



1878. 



Upper disk covered by large swollen radial shields, with minute imbricated scaling in 

 centre, arms wide and thick, with side arm plates much swollen and rounded. Upper 

 arm plates broad, diamond-shape. 



