116 PROP. p. M. DUNCAN S EEVISIOK OP THE 



Genus Heterocentrotus. 

 Colobocentrotus. 

 Echinometra. 

 Stomopneustes. 

 Parasalenia. 



Subfamily JPolyporince (p. 121). 

 Ecliinometridse witli symmetrical tests and having numerous 



pairs of pores. 



Genus Strongylocentrotus. 

 Sphcer echinus. 

 EchinostrepJius. 

 Pseudoboletia. 

 Eurypneustes. 

 JEolopneustes. 



Subfamily Echinometrince. 



Grenus Heteeocentkotus, Brandt (subgenus), 1834-35, Prodr. 



Besc. Anim. p. 265 ; Bee. d. Actes de VAead. St. Fetersh. 



(Additions), 1834-35. A. Agassiz, 1873, Bevision, p. 427. 



Loven, 1874, Etudes, p. 26. J. Bell, 1881, Broc. Zool. Soc. 



p. 420. Be Loriol, 1883, Ech. de Vile Maurice, p. 35. Boven, 



1887, Ech. descr. ly Binnwus, p. 150. 

 Syn. Cidaris (pars), Klein ; Echinus (pars), Linnseus ; Acro- 

 cladia, A. Agassiz, 1846. 



Test large, thick, elliptical in marginal outline, subhemisphe- 

 rical above, convex actinally, and concave from side to side 

 there; elongate transversely, the antero-posterior axis being 

 shorter than the transverse, which passes through ambulacra II. 

 and IV. 



Apical system raised ; periproct small, slightly elliptical ; the 

 right anterior basal plate with a large madreporite ; all basals 

 tuberculate; radial plates excluded, tumid, perforated near the 

 adoral edge ; periproctal plates stout, spined ; anal plates small. 

 The genital pores are sometimes in the interradia. 



Ambulacra broad, straight, wide at the peristome ; interpori- 

 ferous area narrow at the peristome, broad at the ambitus, and 

 diminishing greatly in breadth abactinally ; large plain tubercles 

 . actinally and at the ambitus, replaced abactinally by irregularly 

 placed rows of secondary tubercles. Poriferous zone wide acti- 

 nally, nearly touching at the median line abactinally, more or less 

 broken up by tubercles. Plates compound, high, with as many 



