Cephalaspidea. 43 



have given them the strangest aspect imaginahle, and have 

 caused them successively to be taken for fossil Trionyces and 

 fossil Rays. I have already spoken, in treating of this family, 

 of the affinities, remote it is true, which it presents to the 

 cuirassed fishes of our epoch, the Loricarias and Siluroides. 

 I have nothing further to add on this subject ; but what I 

 should wish to point out, is the truth of this fact, that the 

 different genera of the Cephalaspides already shew a grada- 

 tion, although faintly marked, in their conformation becoming 

 more and more perfect. It is thus that, on the one hand, 

 the winged appendages of the Pterichthys and Pamphractus 

 are lost in the Coccostei and Gephalaspis, where they are 

 replaced by ordinary fins ; while, on the other hand, there is 

 an evident approximation between the Coccostei and the 

 broadly cuirassed genera of the family of Celacanthes, such 

 as Asterolepis and Bothriolepis. The thick and short form 

 of the Pterichthys, and the very incomplete development of 

 their fins, evidently shew that they were fishes of little 

 agility, living in shoals in mud, moving sluggishly and des- 

 tined to become the prey of others. Among the Cephalas- 

 pides, the broad shield with which they are covered, and 

 their eyes situate on the upper side, indicate the same mode 

 of life ; but in them the trunk becomes more moveable, and 

 the tail, the most powerful instrument of motion, is furnished 

 with fins, and becomes fit to execute the most rapid motions. 

 The Coccostei, finally, were evidently, even at this step in 

 the gradation, voracious fishes, as is shewn by their conical 

 sharp teeth, and their long flat and flexible tail. There is, 

 no doubt, a wide interval between this and the formidable 

 armature of the Bothriolepis, and the needle-like teeth of 

 the Dendrodes (Asterolepis); but it will be admitted that 

 there is an advance towards the rapacious character in the 

 family of Cephalaspides, and if we join to this the structure 

 of the plates, the resemblance of the granulated scattered 

 points of the Coccostei to the asterisks of the plates of Astero- 

 lepis, we will soon be convinced that it is not necessary to 

 take a long step to advance from the Coccostei to the cuir- 

 assed Celacanthes. This resemblance will be much greater 

 still if ulterior researches prove that the mailed Celacanthes 



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