386 
DR. MANTELL ON THE PELOROSAURUS. 
sera, of a stupendous terrestrial Saurian, generically distinct from any previously de- 
scribed ; this reptile I propose to name Pelorosaurus Conyheari. 
2ndly. The great probability that the four large anterior caudal vertebrse with the 
chevron bone, termed Cetiosaurus hrevis by Professor Owen, and the two median 
caudals found in the same stratum as the humerus, and at no great distance from it, 
belong to the same species ; and 
Srdly. That certain large bones of Saurians from the oolitic deposits of Oxfordshire, 
at Enstone and at Enslow Bridge, and hitherto considered as Cetiosaurian, may 
appertain to the Pelorosaurus. 
It may perhaps be expected that some estimate should be given of the probable 
magnitude of the reptile to which the humerus belonged; but calculations of the 
length and proportions of the original animal taken from a single bone, or from a few 
detached bones, can afford but vague and unsatisfactory results. With the view, 
however, of conveying some idea of the almost incredible bulk of the Pelorosaurus, it 
may be stated, that in the Gavial or Gangetic Crocodile, the length of the humerus is 
equal to one-eighteenth of the entire length of the animal from the snout to the end 
of the tail; thus in Dr. Grant’s specimen the humerus is 1 foot long; the entire ske- 
leton 18 feet. Computed by this standard the length of the Pelorosaurus would be 
81 feet, and the girth of its body about 20 feet. But if we assume the length and 
number of the vertebrse as the scale, we should have a reptile of relatively very abbre- 
viated proportions ; but in either case, a Saurian far exceeding in size all living types, 
and equalling if not surpassing in magnitude the most colossal of the extinct forms. 
From what has been advanced, we perceive that every addition to the zoology of 
the countries that flourished during the secondary geological ages, affords proof of 
the high development of the terrestrial reptiles, which appear to have enjoyed the 
same predominance in those ancient faunas, as the large Mammalia in those of the 
tertiary and human epochs. The trees and plants associated with the remains of the 
extinct Saurians, manifest by their afiinity to existing forms, that the countries in 
which they grew possessed as pure an atmosphere, as high a temperature, and as un- 
clouded skies, as those of our tropical climes. There are, therefore, no legitimate 
grounds to support the hypothesis that during the “Age of Reptiles” — the period 
when the reptilian class most prevailed — the earth was “ in the state of a half-finished 
planet,” and its atmosphere too heavy from an excess of carbon, for the respiration 
of warm-blooded animals! Such an opinion can only have originated from an im- 
perfect view of the phenomena which these problems embrace. There is as great a 
discrepancy between certain existing faunas and those of modern Europe, as that 
presented by the Wealden : for example, those of Australia, Tasmania, New Zealand, 
and the Galapagos Islands. 
By a singular coincidence, on the same day that I obtained the humerus of the 
Pelorosaurus from Tilgate Forest, I received from my eldest son in New Zealand, 
the most interesting collection of the remains of the extinct gigantic birds of those 
