REPORT ON THE OPHIUROIDEA. 211 



the next plates ; on each lateral side a sharp re-entering curve, where the tentacle issues ; 

 length to breadth, 2 : 2"6. Side arm plates near base of arm not meeting below and 

 scarcely above ; forming broad, abrupt, but not very high ridges. Upper arm plates 

 slightly swollen, about r as broad as long, with a gentle curve without, and a deep curve 

 within. The whole arm is sparsely set with minute points. Disk flat and even, closely 

 set with fine short spines which are sharp and thorny or forked. Eadial shields flat and 

 regular, triangular, with an angle inward, bearing a few spines like those of the disk, and 

 separated by a row of the same; length to breadth, 4 : 2 "5. Near base of arm nine 

 slender, slightly flattened, glassy arm spines, whereof the three lowest are very small. 

 Unlike those of Ophiacantha, these spines are not hollow. Lengths to that of an arm 

 joint, 3, 3, 3"6, 4, 3, 1*6, 1*2, '8, '6 : 2. Three stout, club-shaped, spiniform tentacle 

 scales on the first pore, and usually two on those immediately beyond. Colour in 

 alcohol, straw. 



A younger specimen (Station 192), with a disk of 12 mm., had the upper arm plates 

 longer ; the basal under arm plates did not touch each other ; the scaling of the disk 

 was distinctly marked ; there were three tentacle scales on the basal pores ; the arm 

 spines were seven; lengths to that of an arm joint, 2*2, 4*4, 3, 2"2, 2, 1*5, 1*2 : 1*5. 

 The upper arm spine is sometimes the longest. 



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

 mud. Station 201.— October 26, 1874; lat. 7° 3' N., long. 121° 48' E. ; 102 fathoms 

 stones and gravel. Station 204.— November 2, 1874 ; lat. 12° 43' N., long. 122° 10' E. 

 100 fathoms; mud. Station 209.— January 22, 1875; lat. 10° 10' N., long. 123° 55 

 E. ; 95 to 100 fathoms; mud. Station 219.— March 10, 1875 ; lat. 1° 50' S., long. 146° 

 42' E. ; 150 fathoms ; mud. 



Species of Ophiocamax not herein described. 



Ophiocamax hystrix, Lym. (PI. XLI. figs. 9-11). 



Ophiocamax hystrix, Lym., Bull. Mus. Comp. Zool., vol. v., part 9, p. 232, pi. i. figs. 13-15, 

 1878. 



West Indies; 175 fathoms. 



Ophiothamnus. 



Ophiothamnus, Lyru., Bull. Mus. Comp. Zool., vol. i. part 10, 1869. 



Disk beset with fine thorns or spines, and covered by rather large scales and wide 

 naked radial shields. Teeth, and stout, close-set mouth papillae, but no tooth papillae. 

 Numerous (eight) thorny translucent arm spines, arranged along sides of side arm plates, 

 which are prominent, and nearly or cpuite meet above and below. In each interbrachial 



