EEPORT ON THE OPHIUROIDEA. 119 



plate, l,'8/7,"7 : "5. One stout, oval tentacle scale. Colour in alcohol, grey mottled 

 with pale brown. 



Station 164a.— Lat. 34° 19' S., long. 151° 31' E. ; 400 fathoms; grey ooze. 



Ophiactis 2'>oa, Lym. (PL XX. figs. 13-15). 



Ophiadis poa, Lym., Bull. Mus. Comp. Zoo]., vol. vi., part 2, p. 40, pi. xiii. figs. 356-358, 

 1879. 



Disk scales coarse and thick, with large radial shields ; no spines except a few near 

 the margin. Four rather long and slender arm spines, the upper one longest. Two 

 mouth papillae on each side. 



Diameter of disk 5 mm. Length of arm about 30 mm. Width of arm near disk 

 1 mm. on each side of the short narrow mouth angle are two rather large, squarish, 

 flat papillae, of which the outer one is broader ; at the apex is usually a very small heart- 

 shaped papilla, similar in shape to the larger teeth above it. Mouth shields much wider 

 than long, of a rounded transverse heart shape ; the inner sides a little re-enteringly 

 curved. Side mouth shields of nearly equal width, meeting broadly within. Under 

 arm plates wide shield shaped, bounded without by a broad curve, within by an obtuse 

 or truncated angle, and on the lateral sides by re-entering curves. Side arm plates 

 nearly meeting above and l^elow, not very wide, but projecting, in a well-marked spine 

 crest. Upper arm plates broader than long, fan shaped with an obtuse angle inward. 

 Disk covered with coarse, overlapping scales ; those below regular and smaller, about 

 four in the length of 1 mm. ; those above much larger and more irregular ; in the centre 

 an irregular rosette of large, rounded plates, and in each interbrachial space about tliree 

 radiating rows of elongated scales. The disk margin is sparsely set with small peg-like 

 spines. Eadial shields large, of an angular pear-seed shape, separated wholly by a 

 narrow wedge of two or three scales ; length to breadth 1*5 : 1. Four slender, cylindrical 

 tapering arm spines, the uppermost longest ; lengths to that of an under arm plate 

 1*2, "8, "8, "8 : '5. One large, oval tentacle scale. Colour in alcohol, pale grey. 



Off Tristan d'Acunha ; 1000 fathoms. Off Tristan d'Acunha ; 500 fathoms. Both 

 Station 135.— October 16, 17, 18, 1873 ; rock, shells. 



Ophiactis canotia, Lym. (PI. XIX. figs 16-18). 



Ophiadis canotia, Lym., Bull. Mus. Comp. ZooL, vol. vi., part 2, p. 40, pi. xiii. figs. 353-358, 

 1879. 

 Disk scales larger in centre, where primary plates may be distinguished in a rosette ; 

 no spines, or only an occasional minute one on the margin. Three or four rather long 

 and tapering arm spines. Two mouth papillae on each side. 



(Type specimen from Station 73.) Diameter of disk 5-5 mm. Length of arm about 

 17 mm. Width of arm near disk I'S mm. Two flat, rather large, squarish mouth papillaj 

 on each side of the narrow mouth angle, and one at the apex, similar in form to the teeth, 



