PLATE I. 
DEVONIAN CRUSTACEA. 
Order—M®&ROSTOMATA. 
Sub- Order-—HuRYPTERIDA. 
Fic. 
1. An almost entire body of Pterygotus anglicus, Agassiz, the original specimen 
measuring 23 inches in length, preserved on a slab of grey micaceous sandstone 
from Turin Hill range, Forfarshire. ‘I'wo thirds natural size. See page 34. 
2. A detached head of Pterygotus anglicus, Ag., figured of the natural size, showing the 
marginal eyes (e, e). See page 36. From the Old Red Sandstone, Forfarshire. 
2a. A small portion of the surface of the head, enlarged. 
3. Basal joint of the left maxilliped of Pterygotus anglicus, Ag. (natural size), from the 
Old Red Sandstone, Forfarshire. See page 38. 
4. Pterygotus minor, HW. Woodw. (natural size), from the mdurated shale overlying the 
‘“ Arbroath Paving-stone,” Farnell, Forfarshire. See page 35. 
The above specimens are all from the Museum of James Powrie, Esq., F.G.S., 
Reswallie, Forfar. 
