257 
AN ACCOUNT OF A GANOID FISH FEOM 
QUEENSLAND ( Ceratodus ). 
Br DR. ALBERT GUNTHER, F.R.S. 
Assistant Keeper in the Zoological Department of the 
British Museum. 
[PLATE LXXXVI.] 
The genus Ceratodus lias been established by Professor Agassiz 
for teeth which are found in strata of Jurassic and Triassic forma- 
tions in various parts of Europe and India. These teeth (fig. 3), 
of which there is a great variety with regard to general shape 
and size,* are much longer than broad — sometimes 2 in. long — 
depressed, with a flat or slightly undulated, always punctuated 
crown, with one margin convex, and with from three to seven 
prongs projecting on the opposite margin. They have always 
been found isolated, sometimes with a portion of a bony base 
attached to them. Yet Professor Agassiz pointed out, from 
their shape, that there must have been only two of them in the 
upper jaw and the same number in the lower, that the convex 
margin was directed inwards, and the prongs outwards. No 
other part of the fish to which they belong has hitherto been 
found associated with them ; but Agassiz considered it to have 
been a cartilaginous fish, or more especially a shark — a view 
not so very far from the truth, as we shall see hereafter. 
The discovery of a Ceratodont fish in the recent fauna is 
due to the Hon. William Forster and Mr. Gerrard Krefft, the 
Curator of the Australian Museum at Sydney. Years ago the 
former of these gentlemen had informed Mr. Krefft that there 
existed in the fresh waters of Queensland a large fish with 
cartilaginous backbone, but he was thought to be mistaken 
* Mr. Higgins possesses the largest, and probably most unique, collection 
of Ceratodont teeth from one locality — viz. from Aust-passage near Bristol. 
Among some 300 specimens there are scarcely two which are sufficiently 
alike to be assigned to the same individual. 
VOL. XI. — NO. XLIV. S 
