© Paeril. Secr.i§1]}  CAMBRIAN. - 651 
they were represented by genera indicative of almost every stage of 
development, “ from the little Agnostus with two rings in the thorax, 
and Microdiscus with four, to Hrinnys with twenty-four,” while blind 
genera occurred together with those having the largest eyes.’ 
Besides those just mentioned, other characteristic genera (Fig. 319) 
are Plutonia, Ellipsocephalus, Conocoryphe, Dikelocephalus, Olenus, 
fim aa 





LLL 
ZZ 
| = == Ses Sgr 
4 a = =~, , 
— SSS SS a 
Lf Jef 
Lf/- 


Sl i 
Hh Sel SU 
Qo 
a ae 
Siu NU RS 
WS WW 
fF 
| fh, | 
l 

Fic. 321.—Grovur or Upper CAMBRIAN FOSSILs. 
1, Orthoceras sericeum (Salt.) ; 2, Paleeasterina ramseyensis (Hicks); 3, Lingulella Davisii 
(McOoy); 4, Conularia Homfrayi Salt.) ; 5, Orthis Carausii (Salt.) ; 6, Bellerophon 
arfonensis (Salt.); 7, Paleearca Hopkinsoni (Hicks); 8, Hymenocaris vermicauda 
(Salt.) (and enlarged); 9, Ctenodonta cambrensis (Hicks) (enlarged). 
and Anopolenus. Phyllopod crustaceans likewise occur; the most 
characteristic genus being Hymenocaris (Fig. 321). 
In striking contrast to the thoroughly Paleozoic and long extinct 
order of trilobites, the brachiopods appear in genera some of which 
are still familiar in the living world. Lingula and Discina (Fig. 320), 
1 Q. J. Geol. Soc. xxviii. p. 174. 
