TRANSACTIONS OF THE SECTIONS. 647 



have been but little investigated ; and of fishes, we are acquainted 

 with those only which have been described and figured by 

 Messrs. Sedgwick and Murchison, and which have also been 

 noticed by Cuvier and Pentland. The occurrence of a large 

 number of these was knovni, but no particular information as to 

 their nature was communicated. For a long period M. Agassiz 

 has been anxious to have an opportunity of examining these in- 

 teresting fossils, and this has been afibrded him by the meet- 

 ing of the British Association at Edinburgh. 



The collections which have afforded him the most important 

 materials are the following : That of the Royal Society, which, 

 through the unwearied exertions of the Secretary, Mr. Robinson, 

 contains many remarkable remains from Burdiehouse; Dr. 

 Traill's collection, containing many interesting fishes from Ork- 

 ney; Lord Greenock's extensive series of ichthyolites from the 

 coal formation, and especially from Newhaven. In Professor 

 Jameson's possession is a large head of a fish from the old red 

 sandstone of Forfarshire, of which Messrs. Mui'chison and Sedg- 

 wick have shown M. Agassiz a less perfect specimen, but one 

 which exhibits the other parts of the body. Mr. Torrie sub- 

 mitted to his examination an extensive collection of fossil fishes 

 from Caithness, similar to those described by Messrs. Sedgwick 

 and Murchison ; and also some fishes from Gamrie, first noticed 

 by Mr. Murchison, who also described their geological position. 



Of the fossil fishes not from Scotland which he has seen on 

 the present occasion, he will take another opportunity to speak. 



As to the determination of the Scottish fishes he remarks 

 generally, that they all belong to two orders of the class, viz. 

 some to the order of Placoidian Fishes, Agass. {Cartilagineee, 

 Cuv.) ; but the larger number to the division Ganoidian Fishes, 

 Agass., and two to the section Heterocerci, in which the upper 

 lobe in the caudal fin is longer than the lower. 



In the old red sandstone there are two species from Glammis, 

 Forfarshire, viz. one species of the genus Cephalaspis (Gano- 

 idian), which has hitherto been found in this formation only. 

 The most remarkable characters of this genus are the shield- 

 like covering of the head, which is prolonged backwards in the 

 form of two horns as in the Trilobites, and the manner in which 

 the eyes are placed near each other on the head. The other 

 species belongs probably to the genus Hybodus (Placoidian), but 

 of this only an ichthyodorulite has been seen. 



The fishes from Caithness and Orkney approach one another 

 most nearly ; though amongst the latter there are several new 

 genera, and in all eight species. Those from Caithness seem to 



