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GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



(pars), 1 and also to another, which he classed under " Pygopterus," namely, P. Buck- 

 landi, are so close that it seems unaccountable that they should have ever been placed 

 in different genera; in fact, his having done so seems only to indicate the uncertain and 

 arbitrary nature of the distinction which he drew between Palaoniscus and Amblypterus, 

 as well as his not having fully realised the nature of the special characters of the true 

 Pygvpteri. For in analysing the general descriptions given by Agassiz, of Palaoniscus 

 and Amblypterus respectively, we find ourselves ultimately reduced to the large size of 

 the fins of the latter and the minuteness of their fulcra as the main grounds of 

 distinction ; nevertheless, the fins of " Palaoniscus " striolatus are proportionally just 

 as large, and their fulcra just as minute, as in the two so-called " Amblypteri" referred 

 to above. And with regard to " Pygopterus " Bucklandi, we shall find in the description 

 of that fish that it mainly differs from the present species in its large size and in the 

 proportions and ornamentation of its scales, and can nowise be placed in the same 

 genus with the Pyyopteri of the Permian strata, In fact, according to the restrictions 

 which must now be placed upon the genera Palaoniscus, Amblypterus, and Pygopterus, 

 we are not in possession of any positive evidence of the occurrence of any of the three 

 in Carboniferous rocks. 2 



One point in Agassiz's description of this species requires special notice, viz. his 

 statement that at the anterior margin of the anal fin "on voit encore quelques traces 

 des petites ecailles qui recouvrent ordinairement les nageoires." An examination of 

 the original specimen shows that the real explanation of the appearance here referred to 

 is, that over the greater part of the fin, as is ordinarily the case with the Burdiehouse 

 specimens, the internal aspect of one set of demirays (in this case the left) is seen, the 

 fin having split vertically between the two series ; it so happens, however, that a 

 remnant of the demirays of the other side, showing their external ganoid surfaces, has 

 adhered at the particular spot in question, their short joints having been consequently 

 mistaken for remains of a scaly covering. I have already, in the general description of 

 the structure of this family, shown that the opinion entertained by Agassiz, that the 

 fins of some species of " Palaoniscus " were covered with scales, is untenable. 



Geological Position and Localities. Elonichthys striolatus is a characteristic Fish of 

 the zone of the Burdiehouse Limestone in the Calciferous Sandstone series of the East 

 of Scotland, a zone whose position is above the horizon of the Wardie Shales and 

 below that of the Houston Coal. The best specimens, including the type, have been 



1 An examination of the type specimens of Amblypterus punctatus, Agass., from Wardie, shows that 

 it was founded on two distinct species. One of these, from the peculiarity of its dentition, must form the 

 type of a new genus (Gonatodus, Traq.), retaining the specific term punctutus ; the other is an Elonichthys, 

 closely allied to E. striolatus, and which I propose to call E. intermedins. 



2 The strata at Saarbriicken, Lebach, and Berschweiler, in which the typical Amblypteri occur, as 

 well as the fish-bearing beds of Munster-Appel, Kreuznach, Goldlauter, &c, in Germany, Autun in France, 

 long believed to be of Carboniferous age, are now by continental geologists referred to the Lower Permian 

 (unteres Rothliegendes). 



