Presidents Address. 157 



terini. The heterogeneous nature of Agassiz's " Codacanthi " 

 was pointed out, and the term very properly limited to the 

 peculiar genera Ccelacanthus, Undina, Holophagits, and Mac- 

 ropoma, none of which are, however, found in the Old Eed 

 Sandstone. The remaining Agassizian coelacanths {Holopty- 

 chius, Glyptolepis, etc.) were placed in a new family, that of 

 the Glyptodipterini, and here are also included forms both 

 with rounded and rhombic scales. Pander's family of 

 " Dendrodonts" he will not have, considering it extremely pro- 

 bable that Dendrodus and its allies will turn out to be the 

 teeth of fishes belonging to the Glyptodipterini. But the 

 Eussian author's family of Ctenodipterini and Agassiz's 

 Saurodipterini are retained and likewise placed in the 

 Crossopterygian sub-order, which lastly includes also the 

 Phaneropleurini, constituted by the singular genus Phanero- 

 pleuron. 



The next important point in Professor Huxley's " Essay " 

 is the attention which he drew to the singular ties which con- 

 nect the recent genus Lepidosiren (the Australian Ceratodus 

 being at that time still undiscovered) with the cycloidal- 

 scaled members of the Crossopterygidm. And although he 

 was not fully aware of the extreme closeness of the relationship 

 between the recent Sirenoids and one of his Crossopterygian 

 families, the Ctenodipterini, he, nevertheless, touched the 

 spring which subsequently disclosed to us the true position 

 of that family, when he compared the teeth of Lepidosiren 

 with those of Dipterus. 



On the other hand the American bony pike or Lepidostcus is 

 made the living type of another great assemblage, of which the 

 Old Eed Sandstone genus CheiroUpis " ought perhaps to be re- 

 garded as the earliest known form." To this sub-order of Lepi- 

 dosteidce merely a passing and imperfect notice is accorded, 

 but it is nevertheless clear that the author means it to embrace 

 both the heterocercal Palceoniscidce of the Upper Palaeozoic 

 rocks, and that great array of semi-heterocercal rhombic 

 scaled forms (Lepidotus, Dapedius, Pholidophorus, etc.), which 

 in mesozoic times constituted the great bulk of the Ganoid 

 Order. 



These two great sub-orders of Ci^ossopterygidce and Lepi- 



