THE FISHES 



OF THE 



OLD RED SANDSTONE OF BRITAIN, 



Part IL— THE ASTEROLEPID^. 



INTRODUCTION. 



Eveey beginner in geology is familiar with the general aspect of Pterichthys. 

 Figures of it, unfortunately for the most part antiquated, are to be found in every 

 text-book ; and with its box-like body, oar-like " arms," and scaly tail, it still holds 

 its own in popular teaching as one of the most bizarre in shape of all the creatures 

 whose remains have come down to us from the so-called " Age of Fishes ;" while 

 to the scientific worker its relationship to other forms, fossil or recent, has always 

 seemed to be of the most enigmatical description, though it has also given origin 

 to many curious speculations. 



Pterichthys, discovered by Hugh Miller at Cromarty about the year 1831, and first 

 figured and described by him in his ' Old Red Sandstone' in 1841, the name having 

 been given by Agassiz, is not the only genus of the group to which it belongs. Dis- 

 jointed remains of a closely allied form from the Devonian of Russia were described 

 by Eichwald in 1840, under the name of Asterolepis, from which genus is now derived 

 the designation of the entire family. Another genus described by the same author, 

 also from fragmentary Russian material, is Bothriolepis, which after much confusion 

 and misunderstanding at length occupies its place as a very distinctly marked 

 member of the group. To these, a few years ago, I added a fourth, the little 

 Microbrachius from the Old Red of John o' Groat's, originally collected by the late 

 Mr. C. W. Peach. Whether any other named genera can claim a position in or 

 near the Asterolepidee is a question which may best be discussed in the sequel. 



The remains of these creatures being in many cases extremely fragmentary, 

 their nomenclature is, as might be expected, often cumbered with a complicated 



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