40 



CERATODUS FOSTER I POST-PL I OCENE. 



CERATODUS FORSTERI POST-PLIOCENE. 



By C. W. De Vis. 



The story of the Oeratodus, destined to close in Australia, opens 

 in other lands and far bygone times. There is indeed an interest 

 peculiarly our own in the pages of its record, for Queensland alone 

 has been able to preserve in life the sole and probably the last 

 descendant of its ancient race. But the first appearance of this 

 strange lung-breathing fish was in the beginning of the middle 

 ages — the mediaeval era, so far as is known, of terrestrial life. It 

 lived during the deposition of the mesozoic beds from the Keuper 

 to the Oolite inclusive, and in the care of these sediments left 

 occasional traces of the few forms in which it existed, then to all 

 appearances it died out abruptly. The relics it gave to the rocks 

 were by the nature of its organization rendered obscure and enig- 

 matical, they consisted merely of bodies of one kind so strangely 

 fashioned as to require all the ichthylogical skill of an Agassiz to 

 enable him to identify them as fish organs. He pronounced them 

 to be teeth or rather dental plates, armed on their edges with horn- 

 like projections, and, moved by the resemblance, he named the 

 creature of whose personality they had formed part Oeratodus or 

 * horned-tooth.' 



Unfortunately the specimens at the command of the great 

 ichthyologist were but few in number, more unfortunately scarcely 

 two of them were sufficiently alike to allow him to refer them to 

 the same species; the necessary result was that he established 

 almost as many names as he had examples. Shortly a greater body of 

 materials was brought together in public and private collections, 

 and the fact then became apparent that to continue to give to 

 each different form a distinctive name would end in a reductio ad 

 absurdum, for almost every individual would constitute a species. 

 Observers were therefore forced to the conclusion that whatever 

 the number of species might actually be, the individuals of each 

 differed excessively in the form of their dental plates. Of many 

 hundreds of specimens the majority were believed (and probably, 

 rightly believed) by Professor Miall, their monographer, to belong 

 toa single species, which he aptly named polymorphus: the rest were 



