10 BRITISH FOSSIL CRUSTACEA. 
Order—MEROSTOMATA, Dana, 1852. 
I. Sub-Order—Euryrreripa, Huxley, 1859. 
1. Plerygotus, Agassiz. 
2. Slhimonia, (Page) H. Woodw. 
3. Stylonurus, (Page) H. Woodw. 
4. Eurypterus, Dekay. 
sub-genus Dolichopterus, Hall. 
. Adelophthalmus, Jordan, 
. Bunodes, Eichw. 
. Arthropleura, Jordan. 
. Hemiaspis, H. Woodw. 
. Beapinurus, Nieszk. 
10. Pseudoniscus, Nieszk. 
We) (Oe) 2b Cp CH 
II. Sub-Order—Xuipnosura, Gronovan, 1764. 
1. Belinurus, (Konig) Baily. 
2. Prestwichia, gen. nov. 
3. Limulus, Miller. 
These thirteen genera contain about eighty-three species, which will be found in the 
accompanying Tables, with their geological position and locality, and also the geographical 
distribution of each genus as at present ascertained. 
Nors.—The divisions given in the following Tables for the Devonian strata must not 
be supposed to represent their absolute geological succession ; they are only intended to 
show approximately the English and Scotch equivalents for those rocks which are con- 
sidered to be of Lower, Middle, or Upper Devonian age. ‘The succession of these beds 
is even now undergoing revision so as to render their correlation more consistent with 
those of the Rhine, Belgium, and France. 
