350 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 12, 



May 12, 1847. 



R. E. A. Townsend, Esq., J. Nicol, Esq., and W. A. Provis, Esq., 

 were elected Fellows ; M. C. H. Pander, of St. Petersburg, and M. 

 Vicomte D' Archiac, were elected Foreign Members of the Society. 



The following communications were then read:^ — • 



1. On the Nomenclature of the Fossil Chimceroid Fishes. By 

 Sir Philip Grey Egerton, Bart., M.P., F.R.S., V.P.G.S. &c. 



In a former communication to the Geological Society in 1843, I 

 endeavoured to show that the fossils described by Dr. Buckland in 

 his paper of November 1835, and referred by him to the genus 

 ChimcEra, presented diiferential characters of sufficient importance 

 to warrant their separation from that genus. It was proposed to 

 arrange them under three genera, — ^viz. IschyoduSy of which Chimcera 

 Townshendi was the type ; Elasmodus, typified by Chimcera Hunteri ; 

 and Ganodus, by Chimcera Colei. These generic distinctions were 

 sanctioned and adopted by Professor Agassiz with the further elimi- 

 nation of certain species with falciform lower mandibles, such as 

 Chimcera Mantelli, under the generic name Psittacodon. At that 

 time I had not had an opportunity of examining the specimens dis- 

 covered by Mr. Sibthorpe at Goldworth Hill, and described by Dr. 

 Buckland in 1 838 under the generic n&mes, Fdaphodon axidPassalodon, 

 but having some fragments of the former genus, from Bracklesham 

 Bay, I noticed the close resemblance of these to the other fossil 

 Chimseroids, especially in structure, and alluded to it in the descrip- 

 tion of the upper maxillary bone of Chimcera Agassizi, and more 

 pointedly in a subsequent paragraph referring to the general affinities 

 of the recent and fossil Chimseroids. In the course of the present 

 year I have not only seen the casts of Mr. Sibthorpe's specimens, from 

 which the figures in the ' Poissons Fossiles ' were drawn, but, through 

 the kindness of Mr. Dixon, have had an opportunity of studying a 

 series of specimens of these genera, in a very perfect state of preserva- 

 tion, from Bracklesham Bay. This examination has satisfied me that 

 no distinction, of generic value, can be detected between Edaphodon, 

 and Chimcera Mantelli of Dr. Buckland ; consequently, if the latter 

 be a true Chimcera, the former genus should be cancelled. The 

 arguments I formerly advanced seem now to be generally accepted as 

 warranting the exclusion of all the fossil species, hitherto discovered, 

 from both the recent genera of Chimseroid fishes : indeed Professor 

 Owen considers the distinctions of sufficient importance to exclude 

 these fossils from \]iq family to which the recent forms belong, and has 

 added to Professor Miiller's order Holocephali, a new family under 

 the title Edaphodontidce, for the reception of the fossil genera. I 

 have before stated that Professor Agassiz subdivided the genus Ischy- 

 odus, ranging the species with falciform mandibles under the title 

 Psittacodon. This is a natural and well-characterized division, but 

 as these are the forms which so closely resemble the Bracklesham 



