50 THE VOYAGE OF H.M.S. CHALLENGER, 



Station 224.— March 21, 1875; lat. 7° 45' N., long. 144° 20' E. ; 1850 fathoms; 

 globigerina ooze. 



Ophioglypha costata, Lym. (PL V. figs 1-3). 



Ophioglypha costata, Lym., Eull. Mus. Comp. ZooL, voL v., part 7, p. 76, pi. iv. figs. 92-94, 

 1878. 



Three very short, blunt, peg-like arm spines, evenly spaced. Disk scales few and 

 large. Eadial shields long and separated. Papillge of arm comb close set, flat, and with 

 rounded ends. 



(Type specimen from Station 142.) Diameter of disk 6*5 mm. Width of arm close 



to disk 13 mm. Mouth papUlge five or six on each side, short, square, close set, with one 



larger, diamond-shaped, at apex of jaw. Mouth shield five-sided, with outer edge curved, 



lateral sides nearly straight, and an obtuse angle within; length to breadth 1:1. Side 



mouth shields rather short, lying along inner angle of mouth shield, and meeting \Adthin. 



First under arm plate broad triangular, with an angle within and curved outer edge ; the 



rest are pentagonal, broader than long, with an obtuse angle within, short lateral sides, 



and a long curved outer edge. Side arm plates a little swollen and constricted at their 



inner end, meeting below ; separated above for the first three joints by the upper arm 



plates, of which the first is transverse oval ; the second four-sided, with a curved outer 



edge much wider than the inner ; and the rest triangular, with an angle within and curved 



outer edge. Disk rather flat, and covered by angular plates and a few small rounded scales, 



closely overlapping ; in centre a five-sided rosette of primary plates, which are rounded 



and partly separated by minute scales ; in the interbrachial spaces a single or double row 



of larger and smaller plates. Eadial shields rhomboidal, with the angles slightly 



rounded ; length to breadth 2:1; separated without by a large diamond-shaped plate, 



with its outer and inner angles truncated. The lower interbrachial spaces have a large 



marginal plate and four or five smaller ones ; genital scales wide, bearing on their free 



edge a close-set row of fine papillje, which grow somewhat larger and more rounded above 



to form the arm comb. Three arm spines, minute, blunt, and equally spaced. Tentacle 



scales short and squarish, five on one side and three on the other of the pores of the 



mouth tentacles ; the second pores have three on each side, and those beyond not so 



many. Beyond the disk there are no tentacle scales, and the tentacles are very minute. 



Colour in alcohol, white. 



This species is pretty near Oiyhioglypha hjmani, but is readily distinguished by its 

 flat upper arm plates, those of Ojjhioglyjiha lymani being high and more or less ridged. 



Station 141.— December 17, 1873; lat. 34° 41' S., long. 18° 36' E. ; 98 fathoms; 

 (young); sand and gravel. Station 142. — December 18, 1873; lat. 35° 4' S., long. 

 18° 37' E. ; 150 fathoms ; sand. 



