EEPOET ON THE OPHIUROIDEA. 23 



upper. Arm somewhat flattened, side arm plates not swollen. Eadial shields small, 

 irregular, widely separated. 



(Type specimen from Station 168.) Diameter of disk 9 mm. Length of arm about 35 

 mm. Width of arm close to disk, without spines, 1"8 mm. Four squarish close-set mouth 

 papillse on each side, and two longer and more pointed at angle of jaw. Four short 

 stout teeth, the lowest thickened and rounded. Mouth shields three sided, with a long- 

 angle within, and outer edge much curved; length to breadth I'S : 1'8. Side mouth shields 

 short and thick, wide without ; tapering to a point within, where they just meet. First 

 under arm plate very small, transverse oval in form ; second plate wider without than 

 within, four-sided, having lateral sides re-enteringly curved and a peak without ; those 

 beyond are similar, but nearly pentagonal. Side arm plates broad and thick, meeting 

 below beyond the fourth under arm plate, and above beyond the second upper arm plate, 

 which is fan-shaped, with an angle inward. Disk flat and rather thin, covered with 

 stout, rounded, microscopically tuberculous plates, whereof a large primary occupies the 

 centre, with five others about it, separated in the interbrachial space by a radiating row 

 of two or more scales ; outside these, again, is a row of ten semicircular plates with 

 small scales between ; near each interbrachial margin are two plates side by side ; on 

 the lower interbrachial space are three transverse rows of irregularly shaped plates. 

 Genital scales composed of tlu-ee irregular pieces placed end to end. Genital openings 

 extending from outer edge of mouth shield to margin. Two short, stout, blunt, tapering 

 arm spines placed low on the side arm plate, the lower one twice as long as the upper, 

 and about half as long as an arm joint. One large rounded tentacle scale on the inner 

 side of the tentacle pore. Colour in alcohol pale grey. 



A young specimen with a disk of 2 "8 mm. had arms 5 mm. long. The disk was 

 more arched, and its plates, of course fewer, were microscopically tuberculous. The side 

 mouth shields were very large and swollen, and the mouth shields small. The fii'st under 

 arm plate larger than in the adult, and the rest much smaller proportionately. 



Station 168.— July 8, 1874; lat. 40° 28' S., long. 177° 43' E.; 1100 fathoms; grey ooze. 

 Station 169.— July 10, 1874 ; lat. 37° 34' S., long. 179° 22' E. ; 700 fathoms ; grey ooze. 



Ophiozona antillarum, Lym. (PI. XL figs. 7-9). 



Ophlozona antillarum, Lym., Bull Mus. Comp. Zool., vol. v., part 7, p. 127, pi. vi. figs. 

 152-154, 1878. 



Two short arm spines, upper one longer. Arm of medium height. Side arm plates 

 somewhat flaring outward. Eadial shields large, pointed without and within, nearly 

 joined at their middle point. 



(Type specimen from Station 23.) Diameter of disk 8 mm. Width of arm, without 

 spines, close to disk 1"8 mm. Four short, rounded, close-set mouth papiUge on each side, 

 and two longer and sharper at apex of angle. Mouth shields as long as broad, with an 



