Homosteus, Asinnss, compared luith Coccosteus, Agassiz. 49 



tlie genus Pterichthys of Agassiz, and hence discarding the 

 majority, namely, Asterolejns proper, assigns this name to 

 the minority, to the exclusion of the Agassizian name. In 

 the meantime Prof. Agassiz, then engaged upon his Toissons 

 Fossiles du vieux Gr^s Eouge,' received through Prof. 

 Brown, from Eichwald himself, specimens of his Asterolepw, 

 which had no reference to Pterichthys, but were identical 

 with the genus Chelonichthys established upon specimens 

 brought over from Russia by Sir Roderick Murchison, and 

 of which other specimens were found in the Orkney beds. 

 Oil making 'this discovery, he at once relinquished his own 

 name, Chelonichthys, and adopted Astcrolepis of Eichwald. 

 If now it is sought to supersede Pterichthys of Agassiz by 

 Asterolepis of Eichwald, it is surely just that the term 

 Chelonichthys should be retained for Eichwald's rejectamenta, 

 rather than Homosteus of Asmuss, a name of much later 

 date than that of Agassiz." ^ 



But whatever the specimens from the Orkney beds may 

 have been, if any one will only compare Agassiz's own 

 figure of Aster olepis ornata, Eichwald (" Old Red," tab. 30, 

 fig. 5), with the plate No. 10 in Pander's restoration of the 

 same species (" Placodermen," tab. 6, fig. 1), he will see that 

 this specimen at least, far from having " no reference to 

 Pterichthys," is the median occipital plate of a very closely 

 allied form indeed. Without injustice to the memory of 

 Sir Philip Egerton, to wdiom pala^ichthyological science is 

 indebted for so much valuable work, it is clear that he had not 

 sufficiently gone into this question at least, as the fact above 

 noted was dwelt upon by Pander himself (op. cit., p. 16). 



On the Continent, however, the name Homosteus, Asm., 

 has been adopted for Hugh Miller's fish, and reasons have 

 also been found for maintaining Pterichthys and Astcrolepis 

 as distinct genera, in a supposed difference in the articula- 

 tion of the arms. In the Geological Magazine ^ for this year 

 I have shown that this supposed diagnostic mark is unten- 

 able, at the same time that I have sought to establish 



^ Quart. Journ. Geol, Soc, vol. xvi., 1859, p. 122. 



- Notes on the Nomenclature of the Fishes of the OKI Red Sandstone 

 (Geol. Mng., Dec. III., vol. v., 1S8S, p. 508). 



VOL. X. D 



