100 0>' THE aEXUS CTEXODUS. 



Australian river that was markedly different from all other known 

 existing species,* and this fish was named Ceratodus Forsteri by- 

 Mr. Krefft, late Curator of the Sydney Museum, and I under- 

 stand that he published an account of it in the Second Part of 

 the Proceedings of the Zoological Society for 1870, but I have 

 not had the opportunity of seeing the paper. Dr. A. Griinther 

 was the first, I believe, to give a full description oi Ceratodus; this 

 he did in the Transactions of the Philosophical Society for 

 1871. It was at once seen by palaeontologists and ichthyologists 

 that the detached dental plates called Ctenodus by Agassiz 

 closely resembled those of Ceratodus in their configuration, and 

 they drew the inference that Ceratodus and Ctenodus probably 

 belong to the same family. Further researches into the Coal 

 Measure shales brought to light other remains of the fossil fish, 

 and these mineralized portions of the endo- and exo-skeletons 

 were also seen to resemble closely similar parts of the recent 

 fish. The fact, therefore, that Ctenodus is evidently the proto- 

 type of a fish found only in Australian waters at the present day 

 is my apology for introducing this paper ; which fact is rendered 

 all the more worthy of attention when we think of the immense 

 aeons of ages that must have passed away since the Carboniferous 

 period, during which time we have no trace of either Ctenodus or 

 Ceratodus, nor of any allied form. 



Ceratodus is, I suppose, tolerably well known to most of the 

 ichthyologists of Australia, I shall therefore refer to it compa- 

 ratively seldom, my principal object being to describe what is 

 known of Ctenodus, and incidentally only will I point out the 

 resemblances between those fishes. 



Concerning the remains of Ctenodus, I aai well able to speak ; 

 for Mr. T. Atthey, Mr. T. P. Barkas, P.a.S., and myself, have 

 probably the most complete collections of them in the world, in 

 fact, I know of no other Coal Measure palaeontologists nor an}" 

 Museum that have any other remains than the teeth, unless they 

 have obtained them from the two first-mentioned gentlemen. I 

 brought out specimens of the remains with me from England, 

 but unfortunately some of them have been irreparably injured 

 by the severe knocking about my boxes received while being 

 carried from Sydney to Bombala, my present residence. Sir 

 Philip de Grey Egerton obtained numerous specimens from my 

 father, Mr. T. P. Barkas, which he intended for our Sydney 

 Museum, but on inquiry I find that they have not been received, 

 from some cause or other. 



Ctenodus was so named by Professor Agassiz from some dental 

 plates discovered in the Old Bed Sandstone and Coal Measures ; 



* Since this paper was ■oTitten I have been informed that tlie Key. W. B. 

 Clarke and Mr. A. W. Scott were the fii-st to discover tliis fish's close resem- 

 blance to Agassiz's extinct genus, at least so far as the teeth are concerned. 



