DR A. GUNTHER’S DESCRIPTION OF CERATODUS. 
513 
Indian specimens have been extracted is not yet determined with certainty. These 
teeth have always been found isolated, sometimes with a portion of the bony base 
attached to them ; no other part of the fishes to which they belong has hitherto 
been found associated with them ; and with our present knowledge of the organization 
of the living representative of these extinct species, we can hold out but little hope that 
other parts may have been preserved which can be recognized as the remains of Cerci- 
todus. 
These fossil teeth (Plate XXXI. fig. 10), of which there is a great variety with regard 
to general shape and size, are much longer than broad, sometimes 2 inches long, 
depressed, with a flat or slightly undulated, always punctated crown, with one margin 
convex, and with from three to seven prongs projecting on the opposite margin. Pro- 
fessor 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 w T as directed 
inwards and the prongs outwards — a view also held by Pander*, who made consider- 
able additions towards an accurate knowledge of the structure of these fossils. 
We shall see hereafter that all the characters mentioned are found in the teeth of our 
living fish, that the teeth of some of the fossil species (for instance Ceratodus runcinatus) 
are surprisingly similar to those of the living (see Plate XXXI. figs. 9 & 10), and that 
their position and their number is exactly as shown by Agassiz and Pander (to whom, 
however, the vomerine teeth were unknown). Therefore Mr. Krefft was quite right 
in referring the recent fish to this genusf . 
Geographical Distribution and Habits. 
Before I proceed to the description of the fish, I may notice the little that is known 
of its geographical distribution and habits. Hitherto it has been found in Queensland 
* Ctenodipt. Devon. Syst. p. 33. 
f At a time when nothing was known in this country of Ceratodus forsteri, except the description and pho- 
tographs which were afterwards published by Mr. Kelefet in Proc. Zool. Soc., doubts were expressed as regards 
the propriety of associating a recent fish with a genus living in the Jurassic and Triassic epochs. It may be 
said in reply that fishes very closely allied to, although generically distinct from, Ceratodus and Lepidosiren , 
are known from a much earlier epoch, viz. the Devonian ( Dijpterus , CJieirodus, Conchodus, Phaneropleuron), and 
that the scanty representation and wide distribution of this ichthyic type in the present epoch (one in Africa, 
one in South America, and one in Australia) is a sure proof of its extreme antiquity. Further, there is not 
the slightest evidence that the recent and fossil Ceratodonts differed from each other. It is true we have only 
the teeth for our guidance ; but these are so well marked by peculiar characters, and the recent teeth so similar to 
those of certain extinct species, that we should be better justified in making generic distinctions among the fossil 
forms, than in separating the living from the extinct. Naturalists can be guided only by the evidence before them, 
and not by such vague hypothetical notions as that distance in space or in time has necessarily effected generic or 
other differences. I expressed these views at the meeting of the Zoological Society when Mr. Krefft’s paper 
was read. However, an anonymous reporter in a semipopular journal could not withstand the temptation of 
proposing a new generic name by translating the term “ Wonder of the Rivers ” into Greek, a term more 
expressive of the amount of knowledge of the author than of the peculiarity of the fish. If Ceratodus forsteri 
had proved to be the type of a distinct genus, the honour of naming it would, of course, have been claimed by 
that writer ! 
4 b 2 
