XI 
BRITISH FOSSILS 
Part L—ON THE ANATOMY AND AFFINITIES: OF THE 
GENUS PTERYGOTUS? 
Memoirs of the Geological Survey of the United Kingdom, Monograph L., 
1859, Pp. 1-36. 
THE genus Prerygotus was established by Professor Agassiz, in 
the following note appended to page nix. of his well-known work, 
the “Monographie des Poissons Fossiles du Vieux Gres Rouge” 
(1844) — 
“The Plate A, accompanying this monograph, represents many 
well preserved fragments of one of those gigantic Crustacea of the 
Old Red, collected by Mr. Webster in the neighbourhood of Bal- 
ruddery, in Scotland. Deceived by the scaly aspect of a portion of 
the carapace, I at first believed that this might be the type of a 
peculiar genus-of fishes, and to that class I referred Perygotus, in 
my enumeration of the fossil fishes of the Silurian system, published 
in Murchison’s great work. This genus, founded upon very imperfect 
fragments from the Ludlow rocks, is now well known, from the 
investigations which I have been enabled to make of a new species 
from the Old Red, discovered by Lyell, in Forfarshire, and of which 
Mr. Webster has found more characteristic remains at Balruddery. 
The specimens collected by Lyell are those large scutes, of which I 
have spoken in my ‘Recherches, vol. i. p. 26, and which, in the 
absence of the means of rigorous determination, have been seriously 
taken for the remains of superhuman beings. 
“Dr. Buckland and I, on examining them carefully, convinced 
ourselves that they must be the carapaces of Crustacea ; but it was 
1 Part I. of this Monograph is by Professor Huxley. Tart II. is by Mr. Salter, and is 
reproduced here because without it the plates, and much of Professor Huxley’s portion of the 
Memoir, would be unintelligible. —Epirors. 
