250 HISTORICAL PALAAONTOLOGY. 
conjectured to have commonly supported itself on its hind- 
legs only. 
The Cetiosaur attained dimensions even greater than those 
of the Megalosaur, one of the largest thigh-bones measuring 
over five feet in length and a foot in diameter in the middle, 
and the total length of the animal being probably not less than 
fifty feet. It was originally regarded as a gigantic Crocodile, 
but it has been shown to bea true Deinosaur. Having ob- 
tained a magnificent series of remains of this reptile, Professor 
Phillips has been able to determine many very interesting 
points as to the anatomy and habits of this colossal animal, 
the total length of which he estimates as being probably not 
less than sixty or seventy feet. As to its mode of life, this 
accomplished writer remarks :— 
““ Probably when ‘ standing at ease’ not less than ten feet 
in height, and of a bulk in proportion, this creature was un- 
matched in magnitude and physical strength by any of the 
largest inhabitants of the Mesozoic land or sea. Did it live 
in the sea, in fresh waters, or on the land? This question 
cannot be answered, as in the case of Ichthyosaurus, by appeal 
to the accompanying organic remains; for some of the bones 
lie in marine deposits, others in situations marked by estuarine 
conditions, and, out of the Oxfordshire district, in Sussex, in 
fluviatile accumulations. Was it fitted to live exclusively in 
water? Such an idea was at one time entertained, in conse- 
quence of the biconcave character of the caudal vertebree, and 
it is often suggested by the mere magnitude of the creature, 
which would seem to have an easier life while floating in water, 
than when painfully lifting its huge bulk, and moving with 
slow steps along the ground. But neither of these arguments 
is valid. The ancient earth was trodden by larger quadrupeds 
than our elephant ; and the biconcave character of vertebrz, 
which is not uniform along the column in Cetiosaurus, is per- 
haps as much a character of a geological period as of a me- 
chanical function of life. Good evidence of continual life in 
water 1s yielded in the case of Ichthyosaurus and other Ena- 
liosaurs, by the articulating surfaces of their lmb-bones, for 
these, all of them, to the last phalanx, have that slight and 
indefinite adjustment of the bones, with much intervening 
cartilage, which fits the leg to be both a flexible and forcible 
instrument of natation, much superior to the ordinary oar- 
blade of the boatman. On the contrary, in Cetiosaur, as well 
as in Megalosaur and Iguanodon, all the articulations are 
definite, and made so as to correspond to determinate move- 
ments in particular directions, and these are such as to be 
