This conjecture is further supported by the occurrence in
the strata which contain the bones of the _Iguanodon_ of gigantic
three-toed foot-prints, disposed _singly_ in a double track. These
prints have undoubtedly been produced by some animal walking on
two legs; and they can hardly, with any probability, be ascribed
to any other than this enormous Reptile. Closely allied to the
_Iguanodon_ is the _Hadrosaurus_ of the American Cretaceous, the
length of which is estimated at twenty-eight feet. _Iguanodon_
does not appear to have possessed any integumentary skeleton; but
the great _Hyloeosaurus_ of the Wealden seems to have been furnished
with a longitudinal crest of large spines running down the back,
similar to that which is found in the comparatively small Iguanas
of the present day. The _Megalosaurus_ of the Oolites continued
to exist in the Cretaceous period; and, as we have previously
seen, it was carnivorous in its habits. The American _Loelaps_
was also carnivorous, and, like the Megalosaur, which it very
closely resembles, appears to have walked upon its hind-legs,
the fore-limbs being disproportionately small.
[Illustration: Fig. 209.--Teeth of Iguanodon Mantellii. Wealden,
Britain.]
Another remarkable group of Reptiles, exclusively confined to
the Cretaceous series, is that of the _Mosasauroids_, so called
from the type-genus _Mosasaurus_.
Pages:
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416