XXIII 
DECADE THE TENTH 
PRELIMINARY ESSAY UPON THE SYSTEMATIC 
ARRANGEMENT OF THE FISHES OF THE DEVONIAN 
EPOCH 
Memoirs of the Geological Survey of the United Kingdom. Figures and 
Descriptions illustrative of British Organic Remains. 1861. 
THE endeavour to determine the systematic position of Glypto- 
Jemus, a genus of Devonian fishes, first described and figured in 
Dr. Anderson’s interesting work upon “ Dura Den,” ! and more fully 
discussed and illustrated in the course of the present Decade, has 
gradually led me to reconsider the whole question of the classifica- 
tion of the fishes of this epoch and, eventually, to arrive at results 
which seem to necessitate an important modification of the received 
arrangement of the great order of Ganoidei. 
I propose, in the course of the pages of this preliminary essay, to 
take the reader through the various steps of the argument which 
terminates in this conclusion; and, commencing with a brief enu- 
meration of the most important characters of Glyptolemus, I shall 
proceed to the discussion of the peculiarities of other genera, more 
or less nearly allied to it, with the view of demonstrating, finally, 
that Glyptolemus is a tolerably typical member of a large and well 
defined family of Ganoids, which abounded in the Devonian epoch, 
but whose members have been less and less numerous in more 
modern formations, until, at present, its sole representative is the 
African Polypterus. 
Glyptolemus Kinnairdi (fig. 1, and Plates I. and II.) [Plates 33. 347] 
? Dura Den; a Monograph of the Yellow Sandstone, and its remarkable Fossil Remains. 
1859. * These two plates come in the following paper on ‘‘ Glyptolemus Kinnairdi.” 
