96 EXPLANATION OF THE PLATES. 
OSTRACODA. 
Fig. 6.—a, b, c. ENTOMIS SERRATO-sTRIATA, Sandberger. 
From Sandberger Verstein, Nassau, pl.i., fig. 2. a, natural size; 6 and c, 
enlarged. 
Urrer Devontan.—Petherwin, Cornwall. 
EURY PTERIDA. 
Fic. 7, a-e. Prerygotus ANGLICUS, Agassiz. 
Poiss. Foss. Vieux Grés Rouge, pl. i. 
Mem. Geol. Surv. United Kingdom ; plates iii. to vii. 
From Mem. Geol. Surv. a, Carapace, pl. iii., fig. 1. Reduced to one-fourth 
of natural size. 6. Eye lenses, enlarged, from same plate, fig. 1, d. 
e. Segment (fifth) of a young specimen, reduced to half natural size; from 
pl. iv., fig. 4. d. Telson (twelfth segment) reduced to one-fourth of 
natural size ; from pl.v., fig. 5. e. One of the antennz, reduced to one- 
fourth of natural size; from pl. vi., fig. 4. 
Lower Op Rep Sanpstone.—Balruddery, Perthshire. 
Fic. 8.—Srytonurus Symonpsu, Salter, sp. 
Eurypterus. Salter, Edin., New Phil. Journ. New series, 1857, vol. vi., 
p- 257. Stylonurus,H. Woodward. Journ. Geol. Soc. Lond., vol. xxi., 
p. 486, pl. xiii., fig. 4. Pal. Soe. (1872), p. 124, pl. xxi., fig. 4. 
From Journ. Geol. Soc., Lond., vol. xv., pl. x., fig. 1. Head, reduced to 
one-third of natural size. 
Lower Oxtp Rep Sanpstonr.—Rowlestone, Brecknockshire. 
