Mr. J. S. Bowerbank on Carcharodon Mefiralodon. 121 



D"- 



There is little hope that the remains of perfect jaws, or even 

 fragments of such, should be found in the Crag formation, and 

 it is only therefore through the means of the teeth or vertebrae 

 that we may expect to arrive at anything like an approximation 

 to the history of this gigantic shark. The nearest approach to 

 the size of the teeth of Carcharodon with which I am acquainted, 

 in the recent state, is presented by the jaw of a large specimen of 

 Carcharias glaucus, or blue shark, that was killed at Port Fairy 

 in Australia in 1846, in the presence of a friend of mine. It had 

 so plagued the crew of a whaler by dashing in upon them as 

 they were flinching a whale alongside of the ship, and carrying 

 ofi" large masses of blubber, that they suspended their operations, 

 baited a hook and took it ; and the capture amply repaid them, 

 as the blubber they recovered from its maw produced a barrel 

 and a half of oil. A similar specimen, but slightly inferior in size, 

 was killed by the crew of the Beagle Surveying Ship, Capt. Fitz- 

 roy, and this fish measured 37 ft. in length ; we may therefore 

 safely assume that number of feet as the length of my specimen. 

 Knowing thus the length of the fish, and having the jaw in my 

 possession, it struck me that by the size of the tooth, in propor- 

 tion to the lateral and perpendicular expansion of the jaw, as 

 well as to the whole length of the animal, I might arrive, by 

 comparison with the tooth of Carcharodon Megalodon, at a 

 tolerably accurate approximation to the length and proportions 

 of the latter. 



The length of the largest teeth of the lower jaw of the Austra- 

 lian species, Carcharias glaucus, from the base line to the apex, 

 is 2f inches. The vertical gape of the jaw is 25^ inches, or 

 10^ times the length of the tooth. The horizontal gape is 

 20^ inches, or 8 J- times the length of the tooth. 



The length of the animal being 37 ft., it equals 169| times the 

 length of the tooth. 



If we assume the dimensions of this species and apply them 

 to the great fossil teeth of Carcharodon Megalodon, which is 4|^ 

 inches long, the dimensions of that species will be as follows : — 



10^ lengths of tooth = 47 inches for the vertical gape. 

 8^ „ „ =38 „ „ horizontal gape. 



\m\ „ „ = 65 ft. 2^ in. for the length of the fish. 



And on these proportions a diagram may be constructed, so as 

 to realize to the eye as nearly as possible the vast dimensions 

 of the jaws of the fish to which the tooth of Carcharodon Me- 

 galodon must have belonged. But great as these dimensions 

 appear, I believe them to be considerably under-estimated ; for if 

 we compare the jaw of Carcharias glaucus with that of the common 



