118 PEOF. P. M. DTJKCAlir's REVISIOK OF THE 



confused by the presence of tubercles ; polyserial at the actinal 

 surface, and forming broad areas there. Primary tubercles 

 as elsewhere, plain, in vertical rows, smallest in the poriferous 

 zone and largest at the margin, becoming minute and close 

 actinally. Tentacles heteropodous. 



Interradia broad, but very narrow actinally, with several ver- 

 tical rows of primary tubercles, largest at the margin, and very 

 small and close actinally. 



Peristome polygonal, broad anteriorly, with decided branchial 

 incisions. Perignathic girdle well developed ; ridges long and 

 low ; processes tall, slender, with a top piece, foramen large. 

 Jaws large, with a very long foramen ; teeth keeled. Peristo- 

 mial membrane plain, but with ten small, spined buccal plates. 

 Spines abactinally forming a pavement-like surface, short, hexa- 

 gonal or globose at the end, some larger, longer, flat-ended, and 

 projecting slightly at the ambitus ; actinally short, and either 

 stout or slender, cylindrical and pointed. Intermediate cylin- 

 drical and small spines may or may not exist between the abactinal 

 series, 



Mecent. Zanzibar, Java, Sandwich Islands, Australia. 



Genus Echinometea, Eondelet, 1554, De Pise. Marin, p. 578. 



LutJcen, 1863, Vidensk. Med. f. Nat. 'For. i KjobenJi., pub. 



1864, p. 86. A. Agassiz, 1872-74, Bevision, pp. 282, 431. 



Loven, 1872, Etudes, p. 26 ; 1887, Ech. descr. hy Linnceus, 



p. 153. 

 Syn. Echinus (pars), Linnseus, 1758; Oz^i^ans (pars), Leske, 

 1778 ; Heliocidaris (pars), Agass., 1847. 



Test moderate in size, stout, elongate elliptical in marginal out- 

 line, tumid dorsally ; tumid between the margin and the large 

 peristome, the whole actinal surface concave ; unsymmetrical ; the 

 longer axis, which' passes through amb. I. and interradium 3, 

 does not coincide with the antero-posterior or transverse diameter 

 of the test and is oblique. 



Apical system central; basal plates tuberculate, the madre- 

 porite in the right anterior plate ; radial plates small ; periproct 

 elliptical, its plates small, numerous. Coronal plates numerous. 

 Ambulacra straight ; poriferous zones moderately broad, 

 the 5 to 9 pairs of pores being in bold arcs ; plates high, and 

 composed of a large adoral and small aboral primary and all 

 the others intermediate demi-plates. Tentacles heteropodous. 



