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2. On the Fossil Fishes of the Limestone of Burdiehouse. 

 By Dr Hibbert. 



In this paper the author gave an account of a communication re- 

 ceived by him from M. Agassiz, Professor of Natural History at Neu- 

 chatel in Switzerland, relative to the remains of fishes which had 

 been discovered in the limestone of Burdiehouse, and which had been 

 submitted to his examination. As many of the fish discovered would 

 be explained in his " Recherches sur les Poissons Fossiles," an opi- 

 nion upon a few only was requested. 



The genus found in greatest abundance had been referred by Dr 

 Hibbert to the Palseoniscus, which view was confirmed by M. Agassiz, 

 who, in pointing out its distinction from the Palseoniscus angustus of 

 Autun, which it most resembled, regarded it as a new species. This 

 very characteristic fish of the limestone of Burdiehouse, Dr Hibbert 

 has named Palaeoniscus Bobisoni, in honour of Mr Eobison, General 

 Secretary of the Royal Society of Edinburgh. Another fossil fish of 

 a new and extraordinary genus, received the name of Eurynotus 

 crenatus. A third, which was the first animal relic discovered by 

 Dr Hibbert in the quarry of Burdiehouse. was named, at his request, 

 the Pygopterus Bucklandi. 



The bony rays, of immense dimensions, and beautifully configu- 

 rated, in the possession of the Royal Society of Edinburgh, M. Agas- 

 siz refers to a new genus of fish ; and he proposes to name the indi- 

 vidual to which they belong the Gyracanthus formosus. He is also 

 inclined to refer to the same individual certain teeth found in another 

 locality near Edinburgh. This genus belongs to his Placoidan ordei", 

 and to the family of Cestraciontes, so named from their approach to 

 the Cestracion of Xew Holland. With regard to the alleged Saurian 

 character of the teeth, scales, and some of the large bones discovered 

 in the quarry of Burdiehouse, M. Agassiz was induced to consider 

 them as Sauroid, rather than exactly Saurian, and to assign them to 

 a large sauroid fish, akin to the extant Lepidosteus. In the form 

 of its teeth, and in a very near resemblance of its scales to those of 

 a reptile, the Lepidosteus agrees with Crocodilian families. Nor 

 does this general correspondence fail, even with regard to the inter- 

 nal structure of the animal. M. Agassiz has described the result of 

 an investigation of the swimming bladder of a specimen of the Lepi- 

 dosteus spatula, preserved in spirits, from the dissection of which he 

 was enabled to demonstrate not only that it is a real lung, but that 

 it even approaches closely to the structure of the lungs of reptiles, 



