No. l8.] TRIASSIC FISHES OF CONNECTICUT. 43 



well recognized genera, among which the most satisfactorily 

 known are Coelacanthus proper, Macropoma and Undina. The 

 typical genus enjoys the truly remarkable range from the Upper 

 Devonian to the close of the Paleozoic, and, if the evidence of 

 one or two doubtful forms be accepted, possibly even higher; 

 the remaining genera extend throughout the Mesozoic, and ex- 

 hibit such constancy of structural characters that the family has 

 been frequently cited as one of the most distinct and well defined 

 in the animal kingdom. Huxley, for instance, drew attention to 

 its singular compactness and homogeneity in the following para- 

 graph •} 



" The Coelacanthini, as thus understood, are no less distinctly 

 separated from other fishes than they are closely united to one 

 another. In the form and arrangement of their fins; the 

 structure of the tail and that of the cranium ; the form and num- 

 ber of the jugular plates ; the dentition ; the dorsal interspinous 

 bones ; the pelvic bones ; the ossified air-bladder ; the Coelacan- 

 thini differ widely from either the Saurodipterini, the Glypto- 

 dipterini, or the Ctenodipterini ; but, on the other hand, they 

 agree with these families and differ from almost all other fishes, 

 in the same respects as those in which the several families just 

 mentioned have been shown to agree with one another, viz., 

 the number of the dorsal fins, the location of the paired fins, the 

 absence of branchiostegal rays and their replacement by jugular 

 bones." 



Finally, concerning the extraordinary conservatism and per- 

 sistence manifested by the group of Coelacanth fishes ever since 

 its introduction, the illustrious English biologist whom we have 

 quoted expresses himself as follows:^ 



" Bearing in mind the range of the Coelacanths from the Car- 

 boniferous [since ascertained to extend from the Devonian] to 

 the Chalk formation inclusive, the uniformity of organization 

 of the group appears to be something wonderful. I have no 

 evidence as to the structure of the base and side walls of the 

 skull in Ccelacanthus, but the data collected in the present Decade 



1 Huxley, T. H., Preliminary Essay upon the Systematic Arrangement of the 

 Fishes of 'the Devonian Epoch, prefixed to the Tenth Decade of the Figures and 

 Descriptions illustrating British Organic Remains (1861, p. 20). 



2 Illustrations of the Structure of the Crossopterygian Ganoids. Memoirs of the 

 Geological Survey of the United Kingdom, Decade xii, 1866. Reprinted in the supple- 

 mentary volume of the Scientific Memoirs of Thomas Henry Huxley, 1903, P- 65. 



