110 WHITEAVES ON FOSSIL DEVONIAN FISHES. 
to differ principally in its much greater height or depth in proportion to its length. The 
Canadian fish, in other words, is short and broad in the direction of its height, while the 
Scotch species is long and narrow. Judging by the figures on Plate III of Decade X of 
British Fossils, published as one of the ‘‘ Memoirs of the Geological Survey of the United 
Kingdom,” the length of P. Andersoni is equal to about five and a half times its height, 
whereas, in the larger specimens of P. curtum, the length does not much exceed twice the 
height, and even in the very smallest, the length is not quite three and a half times the 
height. : 
On a cursory examination, the dorsal, caudal and anal fins of the present species 
appear to be continuous, but a closer scrutiny shows that the bases of the caudal and anal 
fins are separated by a short space. 
The many points of resemblance between Phaneropleuron and the living Ceratodus 
Forsteri of Queensland, both in their internal and external structure, have long ago been 
pointed out by Prof. Cope and Dr. Gunther. The notochordal skeleton, lobate paired fins, 
cycloidal scales, triangular patches of palatal teeth, and the peculiar cranial plates of 
Dipterus shew that it too must have been very nearly related to Phaneropleuron. 
