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



Disk high and round, covered above and below with very thin, closely overlapping scales, 

 with one minute circular primary plate in centre of disk. Radial shields small, nearly 

 round, separated by a large angular plate; length to breadth 1-3:1. Genital scales 

 hidden ; along their free edge is a row of very minute, bead-like papillae ; three slim, flat, 

 pointed, nearly equal arm spines, somewhat longer than an arm joint, and equally spaced 

 along the outer edge of the side arm plate. The first pair of tentacle pores, which open 

 into the mouth slit, have six or seven minute tentacle scales, exactly like the mouth 

 papillae, and arranged in an ox-bow figure. The first arm pores have three minute 

 papillae on either side ; those beyond have only two long and rounded scales on the inner 

 side of each pore. Colour in alcohol, white. 



It will be noted that Ophioglypha inermis stands on the limit of Oi^hioglyjoha ; while 

 it has the general look and structure of the genus, it lacks wholly the arm comb, and has 

 only a trace of the papillae along the genital scale below. It seems to go better here than 

 with Ophiocten. 



Ofi" Tristan d'Acunha ; 500 fathoms. 



Ophioglypha deshayesi, Lym. (PI. VII. figs. 13-15 ; PL XXXVIII. figs. 22-25). 



Ophioglypha deshayesi, Lym., Bull. Mus. Comp. Zool., vol. v., part 7, p. 96, pi. ii. tigs. 

 35-37, 1878. 



Side mouth shields large and ovoid. Radial shields and primary plates circular and 

 similar. Disk and arm plates thick, swollen, and closely soldered. Mouth papillae 

 and scales of mouth tentacles thick, squarish, irregular, and crowded. No proper arm 

 comb. 



(Ty[3e specimen from Station 151.) Diameter of disk 18 mm. Length of arm 80 mm. 

 Width of arm close to disk 4 mm. Mouth papillae irregular, crowded, angular, closely 

 soldered, five or six on each side and usually one or two at apex of jaw. Mouth shields 

 small, with long, acute angle inward, and outer edge cleanly curved ; length to breadth 3 : 2. 

 Side mouth shields large, narrow pear-seed shape, with the rounded ends inward, where they 

 meet at one point. Inside the junction of the side mouth shields is a small diamond-shaped 

 supplementary plate, which makes the apex of an angle. First under arm plate semi- 

 circular or transverse oval, with outer edge nearly straight ; the plates beyond are wide 

 triangular, with a truncated angle inward, and outer side a little curved. Side arm plates 

 swollen, nearly meeting below within the disk ; separated above by the upper arm plates, 

 which are broader than long, arched, wider without than within, hexagonal, having outer 

 angles more or less rounded. Disk very thick, covered with rounded plates somewhat 

 obscured by a thick skin ; in the centre above are six large primary plates separated by 



