EEPORT ON THE OPHIUROIDEA. 91 



(Type specimen from Station 192.) Diameter of disk 14 mm. AVidth of arm 3"5 mm. 

 Mouth pajjillse six or seven on each side, and one, diamond-shaped, at angle of jaw. Mouth 

 shields ovoid, slightly pointed within ; length to breadth 2 : TS. Side mouth shields long, 

 narrow, having curved sides, wider without than within, where they nearly or quite 

 meet ; length 2 "3 mm. Genital scales very long and narrow, extending from mouth 

 shield to margin of disk, and bearing on their free edge an irregular row of close-set 

 oblong papillee. Under arm plates triangular, with an angle inward ; in the fii'st two 

 plates the angle is blunt, becoming more acute in those beyond ; outer edge somewhat 

 curved. Tentacle scales only on the first three plates ; they are minute, circular, two in 

 number, set close together and situated very near the inner angle. Side arm plates thick, 

 swollen, barely meeting above and below at the inner angle of the upper and under 

 arm plates. Upper arm plates near base of arm quadrangular, wider than long ; length 

 to breadth 1 -3 : 2 ; towards end of arm they are three-sided. Disk covered in centre 

 with fine delicate scales, among which appear six larger rounded primary plates, which 

 are widely separated, one in the centre, and one in each brachial space. Radial shields 

 oval, swollen, a little wider without than within, separated from each other throughout 

 their entire length by two or three long oval scales mingled with finer. Interbrachial 

 spaces on upper surface occupied by two or three rounded scales, bordered by smaller, of 

 which the largest is on the margin of disk. Under interbrachial space covered by about 

 a dozen thick, rounded, swollen scales, almost concealing the genital scale ; the three 

 largest stand on or near the margin. Four minute peg-shaped arm spines ; three stand- 

 ing together, low on the edge of the plate ; the fourth placed much above them. Colour 

 in alcohol, white. 



Station 192.— September 26, 1874; lat. 5° 42' S., long. 132° 25' E. ; 129 fathoms; 

 mud. 



Opkiomusium liitkeni, Lym. (PI. I. figs. 16-18). 



Ophiommium Lutkeni., Lym., Bull. Mus. Comp. Zool., vol. v., part 7, p. 114, pi. v. figs. 

 138-140, 1878. 



Disk covered by large, angular, smooth, swollen plates, of which the interbrachial 

 marginal is largest. Arms wide and thick, with side arm plates much swollen and 

 rounded, and bearing a spine on their upper surface. 



(Type specimen from Station 192.) Diameter of disk 13 mm. Length of arm 

 about 45 mm. Width of arm close to disk, without spines, 2*5 mm. Four or 

 five large square mouth papillae on each side, with one, srnall and slender, at apex 

 of jaw, all closely joined, those without being deeper than those within. Mouth 

 shields rudely three-sided, having a blunt angle within and a curved outer edge 

 broken by angles. Length to breadth 2-5 : 27. Side mouth shields longer than 



