206 THE FOSSIL ECHINOIDEA 



Fig. 19. Longitudinal profile of the test : natural size. 



20. A portion of the abactinal surface, to show the apical disk and the 



ambulacral petals : magnified. 



21. Abactinal view of the test of a young example : natural size. 



22. Actinal view of the same test : natural size. 



23. Longitudinal profile of the same : natural size. 



24. A portion of the abactinal surface to show the apical disk and the 



ambulacral petals of the young specimen : magnified. 



Genus METALIA, Gray, 1855. 



Test oval, with the margin slightly indented anteriorly by the anteal sulcus, and 

 more or less truncate posteriorly. Abactinal surface arched direct from the margin, 

 which is thin and well rounded, the actinal surface being more or less flat. 



Apical disk compact, excentric in front. 



Paired ambulacra petal oid, usually subequal, in very shallow grooves, which are 

 straight from the apex towards the margin. The anterior pair very widely divergent, 

 nearly horizontal, the posterior pair much less so. Poriferous zones wide, equal; 

 pores equal, wide apart, distinctly conjugate; the immediate apical portion of the 

 zones somewhat atrophied, — the anterior zones of the anterior petals and the posterior 

 zones of the posterior petals more than the companion zones. The odd anterior 

 ambulacrum in a very shallow sulcus ; its poriferous zones composed of minute pairs 

 of pores, obliquely placed and widely spaced. 



Peristome bilabiate, excentric in front. 



Periproct subrotund, on the posterior extremity. 



Two fascioles — peripetaloils and subanal. The peripetalous slightly sinuous, and 

 extending to the anterior margin ; the interradia within its boundary often with some 

 large and widely spaced tubercles. The subanal fasciole is large, subreniform, and 

 complete. 



Tubercles very small and crowded on the abactinal surface, large and well-spaced 

 on the actinal. 



1. Metalia Soweebti, d'ArcUac, sp. Plate XXXV, Figs. 10-16. 



Brissopsis Sowerbyi, d'Archiae (1850), Hist, des progres de la Oeol. t. iii. p. 251. 



Brissopsis ? Sowerbyi, d'Archiae Sf Haime (1853), Descrija. An. foss. de VInde, p. 220, pi. xv, figs. 7a, b. 



The following is the diagnosis of this species given by MM. d'Archiae and 

 Haime: — 



Body slightly elongate, expanded laterally in the median region, rather high, 

 especially in front ; apex situated nearly at the anterior third of the major diameter ; 

 four generative pores closely approximated, the posterior the largest ; the four ocular 

 pores very distinct; the odd anterior ambulacrum forming an expanded groove, 

 tolerably pronounced and bounded on each side by a rather thick subgibbous carina- 

 tion. The petaloid ambulacra are grooved, straight, narrow, of medium size ; the 



