Vol. 60.] EDESTL'S IN THL; COAL-MEASURES OF BRITAIN. 9 



Discussion. 



Dr. A. Smith Woodward confirmed the Author's interpretation 

 of the fossil exhibited, and remarked on the imperfection of our 

 knowledge of the marine Upper Carboniferous fishes. The frag- 

 mentary character of the known remains of Edestidse prevented 

 the formation of any definite judgment as to their true nature. 

 He regarded the fossils named Edestv.s and Helieoprioii as the fused 

 teeth of sharks, and alluded to the discovery of analogous whorls 

 of teeth in the mouth of a Lower Devonian shark described by 

 Dr. Traquair. He did not think that the more flattened rows of 

 teeth needed a different interpretation from that of the more spiral 

 whorls. 



The Author, in reply, called attention to the use which the 

 living ' sawfish ' (Pristis) makes of its toothed rostrum, as indicating 

 a possible function of the Helicoprion-spiTa.1, if (as has been supposed) 

 this was placed in front of the head. 



