598 • BEISSUS UNICOLOK. 



Eiissus unicolcr 



! Brissus uuicolor Ki.rcix, 1734. Nat. Disp. Ech. 

 (Sec Pari II. p. 857.) 



PL XXIT.f. i, 2; PL XXXVII. f. 19. 



West India ; (.'ape Verde Islands ; Mediterranean. 



(BRISSUS.) Metalia. 



Plagionotus (Agass.). 1 S4 7 (non Mci.s. 1842). 

 Metalia Gray, 1855, Cat. Rec. Ech. (emend.) 

 (See Pari II. p. 360.) 



Metalia africana 



! Plagionolw africanus Verrill, 1871. Notes on Radiata, p. 569. 

 ! Mi 'alia africana A. Ac, 1872, Rev. Ech., l'l. I. p. 144. 



It is with considerable doubl thai this species is maintained as distinct 

 from the West Indian M. pectoralis. The few specimens of the latter ex- 

 isting in our collections show a verj wide range of variation, find, as several 

 of the West Indian species are also found on the West Coast of Africa, this 

 may prove to be only a variety of our West Indian species ; although the 

 principal differences noticed in the two specimens examined by Mr. Verrill 

 may prove sufficiently constant, with additional material, to maintain their 

 specific identity. These differences consist in the smaller number of plates 

 covering the anal system (in M. africana), the presence of large tubercles on 

 the anterior or lateral interambulacra. above the peripetalotis fasciole, the 

 comparatively narrower peripetalous fasciole. and especially the outline of 

 the actinostome, which is broad, transversely, in the African specimens, and 

 much more rounded anteriorly and long in the West Indian specimens. 



Metalia maculosa 



Echinus maculosus Gmel., 1788, I.ixx. Syst. Nat. 



\ Metalia \ Agass, 1872, Rev. Ech., Pt. I. p. 144. 



PL XXI". f. s 9; PL 'XXVI. f. 89; PL XXXVIII. f. 29. 



Test depressed ; outine from above elliptical, slightly indented at the 

 anterior edge, truncated posteriorly. Greatest breadth across the extremity 

 of the posterior petals. Vertex posterior ; apical system more central 

 than in M. sternalis ; ambulacra! petals small, narrow, slightly sunken ; 

 peripetalous fasciole, with one small re-entering angle, near the posterior 



