( 595 ) 





XXI. — On Thelodus Pagei, Poivrie, sp. from the Old Red Sandstone of Forfarshire. 

 By Ramsay H. Traquair, M.D., LL.D., F.R.S., Keeper of the Natural History 

 Collections in the Museum of Science and Art, Edinburgh. (With a Plate.) 



(Read 4th July 1898.) 



The remarkable fossil fish which forms the subject of the present communication 

 belonged originally to the late Mr Powrie of Reswallie, and was acquired, along with the 

 rest of his collection, by the Edinburgh Museum in 1892. 



The specimen was obtained by Mr Powrie in a quarry of the Lower Old Eed Sand- 

 stone at Turin Hill, near Forfar. 



In his monograph on the Fossil Cephalaspidce of Great Britain, published in 1870, 

 (p. 41), Professor E. Ray Lankester refers in the following terms to the specimen in 

 question : — 



" A very remarkable specimen of shagreen-like structure has been discovered by Mr 

 Powrie in Forfarshire, in beds which have furnished Cephalaspis. As I have not been 

 able to assign it to Cephalaspidian fishes, though it may possibly be connected with 

 them, I only allude to it here. It consists of a surface covered with minute spinous tuber- 

 cles, the whole having the appearance of a fossilised piece of shagreen, and its shape is 

 more or less that of a Cephalaspid, with head and body. The spinous tubercles on some 

 species of Cephalaspis suggested the idea that this might belong to the lower surface 

 of one of these fishes, covering in the ventral aspect of the head and the ventral series 

 of scales ; being detached, as it were, in this part of the animal, but adhering closely to 

 the deeper aponeurotic layers of the exoskeleton in the superior parts, and forming the 

 characteristic tuberculated surface of the shield and scales. There is, however, no proof 

 of its connection with these fishes, and it seems more probable that it belongs to some 

 early representative of the Sharks and Rays (representative, perhaps, only in the 

 character of its dermal ossifications) than that it is the ventral surface of a 

 Cephalaspid." 



In the same year, however, Mr Powrie himself published a paper in which he named 

 the fish in question Cephalopterus Pagei, and gave likewise a rough pen and ink 

 drawing of it.* His description of the species is as follows :— 



" Head and anterior portion of body very depressed, sub -elliptical, and truncated 

 posteriorly ; pectoral fins forming its outer posterior angles, which are rounded ; posterior 



* " On the Earliest Known Vestiges of Vertebrate Life ; being a Description of the Fish Remains of the Old Red 

 Sandstone of Forfarshire," Trans. Geol. Soc. Edin., vol. i. pp. 284-301. Paper read 16th April 1869, published 1870. 



VOL. XXXIX. PART III. (NO. 21). 4 X 



