78 PKOF. p. M. Duncan's revision of the 



Grenus Echinothrix, Peters, 1853, Ahh. k. Akad. Wiss. Berlin, 

 (1854), p. 114. A. Agassiz, 1872-4, Bevision, p. 413. Bun- 

 can, 1885, Journ. Linn. Soc. (Zool.), vol. xix. pp. 101 aud 

 202. Loven,18H7, Bch. desc. hy Linnceus, -p. 137, (Amended.) 



Syn. Garelia, Gray ; Savignia, Desor. 



Test large, thin, tumid, moderately higli, depressed, broad. 



Apical system large, more or less sunken ; basals large and 

 projecting into the interradial spaces ; radials small and entering 

 the ring ; the periproct large, with a close pavement of plates. 

 Coronal plates numerous. 



Ambulacra tumid, narrow, with several vertical rows of very 

 small tubercles, which are crenulate and perforated, diminishing 

 in number actinally ; plates numerous, low, broad, composed o£ 

 three primaries, with the sutures convex towards the tubercle ; 

 near the peristome the adoral component is small and excluded 

 from the interradial suture. Pairs of porey large, in close arcs, 

 the adoral pair nearest the ambulacral median line, forming, with 

 others, a vertical series. 



Interradia with a bare median space, sunken, elsewhere several 

 vertical rows of large primary tubercles, crenulated and perfo- 

 rated, scrobiculate, diminishing in number abactinally. 



Peristome large, with deep branchial incisions and tags ; mem- 

 brane with small plates. Perignathie girdle with very broad, low 

 ridges ; processes expanded above, opening large. Jaws with the 

 foramen of the pyramid an open arch, the teeth grooved. Spines 

 slender, long, striated, verticillate, more or less solid. 



Becent. E. coast of Africa, Pacific Islands, Japan, Philippines, 

 E. Indian Islands, E-ed Sea. 



Genus Asteoptga, Gray, 1825, Ann. Bhil. vol. xxvi. p, 246. 

 Beters, 1853, Alh. Jc. Akad. Wiss. Berlin (1854), p. 110. 

 A. Agassiz, 1872-4, Bevision, p. ^7 \ 1881, Beport on 'Chal- 

 lenger'' Bellini, p. 72, pi. x. a. fig. 9. Duncan, 1885, Journ. 

 Linn. Soc. (Zool.), vol. xix. p. 106, pi. v. (Amended.) 

 Test large, tumid at the ambitus, depressed, thin, more or less 

 flexible ; ambulacra bulging. 



Apical system large ; basals large, triangular, elongate ; radials 

 much smaller, narrow, and entering the periproctal ring. Mem- 

 brane with circular rows of plates. 



Ambulacra narrow, convex, with two vertical rows of large, 



