REPORT ON THE OPHIUROIDEA. 267 



but only near their ends. Teeth, but no tooth papillse, and only a few small mouth 

 pajDillse irregularly arranged high up on the sides of the mouth angle. At the tips of the 

 twigs the side arm plates are like long flaps, free of the arm and bearing at their ends a 

 pair of little hooks. Further inward they cling close to the arm and take on the usual 

 form of such plates, while the hooks become spine-like tentacle scales (or arm spines). 

 The side arm plates, connected below by a solid under arm plate, are continued upward 

 by swollen lime nodules homologous with upper arm plates. Large side mouth shields, 

 but no mouth shield proper. Two small genital openings in each interbrachial space, 

 between which is a fine madreporic pore leading into a stone canal. 



Species of Trichaster not herein described. 



Tvichaster palmiferus, Agas., Mdm. Soc. Scien. Nat. Neuchatel, p. 193, 1835; Mlill. 

 and Tr., Syst. Ast., p. 120, 1842. 



Eunjale palmiferurn, Lmk., Syst. Anim. sans Vert., vol. ii. p. 539, 1801 : Encycloped. Metli., 



p. 384, pi. cxxvi. 

 Astrophyton palmiferurn, Bronn, Syst. d. urweltl. Pflanz., pi. ii. fig. 3. 

 Trichaster fiagellifer, V. Mart. Wieg. Archiv, vol. xxxii. p. 87, 1877. 

 India. 



Trichaster elegans, Ludwig, Zeits. fur Wissen. Zoologie, vol. xxxi. p. 59, 1878. 

 Great Ocean. 



Astroclo7i. 



Astrodon, Lym., Bull. Mus. Comp. Zool., vol. vi., part 2, 1879. 



Arms beginning to branch at a considerable distance from the disk, and ha\'ing but 

 few forks, nearly as in Trichaster. Disk rising well above the arms, and granulated, as 

 are the latter. The tips of the twigs are encircled at each joint by a double belt of hook- 

 bearins grains. Along the under .surface of the base of the arm are two longitudinal 

 lines of large, transverse slits, a pair to each joint, from which issue short tentacles ; and 

 above these on either side is a row of peg-like tentacle scales. Mouth angles naked on 

 their sides, but with a bunch of spine-like papillae at the apex. Two very large genital 

 openings in each interbrachial space. 



Astrodon propugnatoris} Lym. (PL] XXIV. figs. 6-11). X 



Astrodon propugnatoris, Lym., Bull. Mus. Comp. Zool., vol. vi., part 2, p. 69, pi. xviii. figs. 

 481-486, 1879. 



Animal covered above by a closely soldered granulation, in which appear numerous 



1 Dr. Carpenter has happily translated Challenger hy xpo'|tt«^05, the Homeric word for a champion who stood in 

 front of the line of battle and challenged the leaders of the enemy. Proptignator is a verbal translation, although it seems 

 usually to signify rather a defender. I am told by high authority, however, that its present use is allowable. Goliath 

 was such a challenging champion, but he is described in the Vulgate as vir spurius, an expression not applicable here. 



