292 GENERAL CONCLUSION. 
Conclusion. 
In the facts before us, we have an unmter- 
rupted series of evidence, derived from the family 
of Fishes, by which both bony and cartilagi- 
nous forms of this family, are shewn to have 
prevailed during every period, from the first 
commencement of submarine life, unto the pre- 
sent hour. The similarity of the teeth, and 
scales, and bones, of the earliest Sauroid 
Fishes of the coal formation (Megalichthys), 
to those of the living Lepidosteus, and the cor- 
respondence of the teeth and bony spines of 
the only living Cestraciont in the family of 
Sharks, with the numerous extinct forms of that 
sub-family, which abound throughout the Car- 
boniferous and Secondary formations, connect 
extreme points of this grand vertebrated division 
of the animal kingdom, by one unbroken chain, 
more uniform and continuous than has hitherto 
been discovered in the entire range of geological 
researches. 
It results from the review here taken of the 
history of fossil Fishes, that this important class 
of vertebrated animals presented its actual gra- 
dations of structure amongst the earliest inha- 
bitants of our planet ; and has ever performed 
the same important functions in the general 
economy of nature, as those discharged by their 
living representatives in our modern seas, and 
