BRITISH ASSOCIATION. 



257 



in this sense, the term was extremely convenient, as ex- 

 pressing the explanation attached to a set of phenomena. 



Report on the Fossil Fishes of the Devonian System, or Old 

 Red Sandstone, by Prof. Agassiz. 



The author commenced by describing the favourable 

 circumstances under which he had examined these remains. 

 The rapid progress which had been made in developing the 

 riches of these deposits since 1834, when Dr. Fleming and 

 Messrs. Sedgwick and Murchison first pointed out the exis- 

 tence of a few scales at Cleishbinnie, and afterwards dis- 

 covered two new genera of fish at Caithness ; four species 

 only were then known, and of these but one was figured. 

 The researches of Dr. Traill and Messrs Murchison and 

 Lyell, had enabled him in a former report to raise the 

 number of genera to ten, and the species to seventeen. 

 Since that time such an impulse had been given to those 

 researches by Mr. Murchison^s work on 'The Silurian 

 System,^ that on again visiting Scotland in 1840, he had 

 the opportunity of examining double the number of genera, 

 and triple the number of species, which had been lately dis- 

 covered and not yet described. On this occasion, one of 

 the most remarkable forms of organic life, and one entirely 

 new, the Pterichthys (so named by him from its possessing 

 appendages resembling wings), was discovered by Mr. 

 Miller of Cromartie. Another form, also new, and equally 

 curious, the Coccosteus, was discovered at Caithness, by 

 Mr. Sedgwick and Mr, Murchison, opening to the com- 

 parative paleeontologist a field of research as fruitful as the 

 discovery of the Plesiosauri and Ichthyosauri a quarter of a 

 century before. These two genera presented characters so 

 different from any known fish, as to have been referred, in 



