PLATE XIX. 



UPPER SILURIAN CRUSTACEA. 



Order — M e ro sto m at a . 



Sub- Order — Eurypterida. 



Figs. 1 — 4. — Slimonia acuminata, Salter, sp. P. 106. 



Fjo. 



1. The largest perfect head-shield known. 



(o, o), the compound eyes. 

 {?, e), larval eye-spots. 

 Drawn the natural size. 



2. One of the compound eyes of a small individual, enlarged four times in order to 



show the facets. 



3. A detached leaflet from the branchiae of the natural size. P. 115. 



4. A series of branchiae preserved united. Drawn of the natural size. P. 115. 



From specimens in the British Museum. 

 Formation. — Uppermost Ludlow Rock. 

 Locality. — Lesmahagow, Lanarkshire. 



