﻿PLATE IV. 



DEVONIAN CRUSTACEA. 



Order — Merostomata. 

 Sub- Order — Eurypterida. 



Basal joint of a left maxilliped (or ectognatk) of Pterygotus anglicus, Agassiz, figured 

 of the natural size, from the Devonian of Forfarshire. See page 38. 



m, the toothed mandibular border ; s, the point of articulation for the proximal end of the 

 swimming-foot. (See Plate VIII, fig. 1, 6.) 



The original specimen is preserved in the British Museum. 



