82 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Journal*. Immediately after, others exerted themselves to obtain 

 for us the loan of the great Scotch Eurypterus, made so famous by 

 Dr. Hibbert, and which was found, not in the Coal proper, but in the 

 Carboniferous Limestone of Linlithgow. 



No sooner had the Scotch Euryptems been taken in hand, than I 

 found a new one in our own Coal, almost as large. A friend in 

 Staffordshire sent me a unique form from the coal-measures of 

 that district, the remarkable spined Eurypterus described below. 

 A new Shrimp turned up from the Millstone Grit of Yorkshire, under 

 the hammer of the well-tried Collector of the Geological Survey, 

 Richard Gibbs. A beautiful Crustacean, illustrating new points in 

 the Palaeozoic history of the class, came to light in Dumfriesshire ; 

 and, while considering what to do with all this material, Dr. Dawson 

 of Montreal sent me his Carboniferous and Devonian novelties to 

 describe for the Society. 



Eerypterus Scouleri, Hibbert. 



Eurypterus Scouleri, Hibbert, Trans. Roy. Soc. Edinb. vol. xiii. 

 p. 179, pi. 12. figs. 1-5 ; Eidothea, Scouler, Cheek's Edinb. Journ. of 

 Nat. and Geograph. Science, vol. iii. p. 352, pi. 10. 



For an opportunity to examine this fine head, long ago described 

 by Dr. Hibbert in the ' Transactions of the Royal Society of Edin- 

 burgh,' I am indebted to Mr. James Smith, of Jordan Hill, Glasgow, 

 and Dr. Rankin of that place. It was kindly lent me by the 

 Council of the Andersonian Institution for a fresh description and 

 figure, that of Dr. Hibbert being incomplete. The large carapace 

 is all but perfect (a portion of the right side only being absent), and 

 in its natural condition uncompressed ; so that the great convexity 

 of the form is manifest. The carapace and the two front body- 

 rings (preserved so as to show both their dorsal and ventral surfaces) 

 are retained in this specimen, attached to one another; and, bent 

 upward beneath it, is a large fragment of a swimming-foot, con- 

 sisting of the first four joints, all imperfect. 



The dimensions are as follows : — Carapace, forming more than a 

 quarter of a sphere, 4| inches long by fully 6| broad, and the con- 

 vexity such as to follow the shape of the body-rings, which are 

 4| inches broad and 3 inches deep from back to front. The greatest 

 convexity is in the region behind the eyes, which are placed, not 

 quite halfway up the head, near together, only an inch and a quarter 

 apart. They are divided from each other by a pair of inflated tri- 

 angular lobes, with a small central process lying in the deep hollow 

 between them. This central prominence, the round approximate eyes, 

 together with the rough, hirsute, spinous character of the convex 

 region behind the eyes, give the whole head much the appearance of 

 a deformed human countenance. 



The outline of the carapace is about two-thirds of a circle, the 

 short, broad, spinous ears being curved inwards, not outwards ; and 

 the posterior edge is only gently arched. A very distinct depression 

 indents the front, but does not affect the actual anterior margin. 

 * I have, however, since seen another fragment in the Hope Collection at Oxford. 



