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



Opkiozona nivea, Lyra., III. Cat. Mus. Comp. Zool, No. viii., part 2, p. 9, 1875, out- 

 line figs. 85, 86 ; Bull. Mus. Comp. Zool., vol. v., part 7, p. 128 ; vol. v., part 9, p. 221. 

 Station 24.— March 25, 1873; off Culebra Island ; 390 fathoms ; mud. 



Ophiozona insularia, Lyra. (PI. XL figs. 10-12). 



Ophiozona insularia, Lyni., Bull. Mus. Comp. Zool., voL v., part 7, p. 126, pi. vi, figs. 

 149-151, 1878. 



Four short, nearly equal arm spines. Arm high. Side arm plates swollen, and 

 strongly flaring outward. Radial shields large, rounded triangular, widely separated. 



(Type specimen from Station 173.) Diameter of disk 6 mm. Length of arm about 18 

 mm. Width of arm close to disk, without spines, 1*6 mm. Five short, squarish, close-set 

 mouth papillse on each side, one large spearhead shaped at apex of angle. Mouth shield 

 longer than broad, with a very deep curve without, and an angle within; length to breadth, 

 1 : "8. Side mouth shields short and thick, rather wider without than within where they 

 meet. First under arm plate very small, tranverse oval in shape ; second, third, and 

 fourth plates large and five-sided, with inner angle truncated, small re-entering curves on 

 the lateral sides, and outer edge slightly curved ; beyond, they approach a fan-shape, with 

 an angle inward. Side arm plates broad, swollen, and flaring outward, just meeting below 

 beyond the fifth under arm plate, and above beyond the fifth or sixth arm plate, which is 

 fan-shaped, with an angle inward. Disk rounded pentagonal and flat, with a large central 

 plate, and five others round it, separated from each other by a wedge-scale ; interbrachial 

 spaces filled by four angle plates, a large one within, outside this two smaller, and then 

 a squarish marginal plate. Radial shields swollen, longer than wide, three-sided, with 

 angles rounded, separated throughout their entire length by a wedge of three plates 

 whereof the innermost is largest and connects with a primary plate ; length to breadth 

 1*3 : 1. Lower interbrachial space covered by two very irregular transverse rows of 

 long rounded plates. Genital scales long and narrow, curved and tapering. Four short 

 blunt arm spines, the three lowest longest, and about half as long as an arm joint. Two 

 tentacle scales on the first two pairs of tentacle pores, a small one within and larger one 

 without ; beyond this there is only one large round scale. Colour in alcohol, white. 



A smaller specimen, whose diameter of disk was 3 '5 mm., was similar, except that the 

 disk plates fewer and more regular, and the radial shields were scarcely separated. 



Station 173. — July 24, 1874; off Matuka, Fiji Islands; 310 fathoms; coral. 



Ophiozona stellata, Lym. (PI. XL figs. 13-15). 



Ophiozona stellata, Lym., Bull. Mus. Comp. Zool., vol. v. part 7, p. 125, pi. vi. figs. 147, 148, 

 1878. 



Two short arm spines placed low on the plate, the lower one twice as long as the 



