66 J. W. DAVIS ox PISH-EEMAINS POUND IN THE 



is comparatively short and much stronger ; but otherwise they are 

 very similar both in form and method of attachment. 



Hitherto the fishes found in the Coal-measures have been classed 

 as members of one of the two great groups which formed the 

 fish-fauna characteristic of the Carboniferous age, viz. the Ganoids 

 and the Elasmobranchs. In the genus Ostracacanthus, if the 

 diagnosis I have attempted should be substantiated by future 

 discoveries, there is evidence that fishes closely allied to some of 

 the more abnormal forms of the Teleosteans of the present day 

 existed during that period. Prof. Huxley* has expressed the 

 opinion that several of the fishes of the Devonian rocks are closely 

 related to the modern Siluroids. In the structure of the head of 

 Ooccosteus the general arrangement of the bony exoskeleton much 

 resembles that of the tropical fish Clarias ; while the pecuhar form 

 of the mandibles and the expansion of the bony elements usually 

 considered to be homologous with the coracoid and radius of other 

 fishes, so as to form a large ventral shield, offer many points of 

 resemblance to the Siluroid Loricaria. The Devonian PtericlitJiys 

 is also in several ways closely related to the modern Siluroids; 

 and the fossil fish OepJialaspis has also certain resemblances to 

 GalUclithys and Loricaria. Prof. Huxley remarks : — " At any rate, 

 I think the prima facie case in favour of the Teleostean nature 

 of Ooccosteus is so strong that it can no longer be justifiable to 

 rank it among the Ganoids sans phrase ; but even those who will 

 not allow it to be a Teleostean must attach to it the warniug 

 adjunct of incertoi sedis '^ ; and, further, " Why should not a few 

 Teleosteans have represented their order among the predominant 

 Ganoids of the Devonian epoch, just as a few G-anoids remain 

 among the predominant Teleosteans of the present day? When 

 it is considered that an ichthyologist might be acquainted with 

 every freshwater and marine fish of Europe, Asia, Southern Africa, 

 S. America, the Indian archipelago, Polynesia, and Australia, and 

 yet know of only one Ganoid, the Sturgeon, a fish so unlike the 

 majority of its congeners that a naturalist might be well acquainted 

 with almost all the fossil Ganoids and yet not recognize a Sturgeon 

 as a member of the group, it will not seem difiicult to admit the 

 existence of a Teleostean among the Devonian Ganoids, even though 

 that Teleostean should in some, even important, points differ from 

 those with which we are familiar." 



It may be somewhat premature, considering the fragmentary 

 nature of the specimen, to express an opinion that a fish resembling 

 the Teleostean Ostracion has been found in the Coal-measures. The 

 spine and its peculiar attachment, however, are totally different 

 from every other form of Ichthyodorulite with which I am conver- 

 sant, and, providing the evidence on which Prof. Huxley bases the 

 arguments given above is held to be correctly applied, and that the 

 oldest Devonian fishes have many points of similarity and relation- 

 ship with the Siluroid family of the Teleosteans, the probability of 



* Mem. of the Geo!. Survey, decade x. 



