THE JURASSIC PERIOD. 249 
possess some weighty points of relationship with the so-called 
‘‘ Pachydermatous ” Quadrupeds, such as the Rhinoceros and 
Hippopotamus. The most important Jurassic genera of 
Deinosauria are Megalosaurus and Cetiosaurus, both of which 
extend their range into the Cretaceous period, in which 
flourished, as we shall see, some other well-known members 
of this order. 
Megalosaurus attained gigantic dimensions, its thigh and 
shank bones measuring each about three feet in length, and its 
total length, including the tail, being estimated at from forty 
to fifty feet. As the head of the thigh-bone is set on nearly 
at right angles with the shaft, whilst all the long bones of the 
skeleton are hollowed out internally for the reception of the 
marrow, there can be no doubt as to the terrestrial habits of 
the animal. The skull (fig. 180) was of large size, four or five 
Fig. 180.—Skull of Megalosaurus, on a scale one-tenth of nature. Restored. 
(After Professor Philli ps.) 
feet in length, and the jaws were armed with a series of power- 
ful pointed teeth. The teeth are conical in shape, but are 
strongly compressed towards their summits, their lateral edges 
being finely serrated. In their form and their saw-like edges, 
they ‘resemble the teeth of the “ Sabre-toothed Tiger” (AZachat- 
vodus), and they render it certain that the Megalosaur was in 
the highest degree destructive and carnivorous in its habits. 
So far as is know n, the skin was not furnished with any armour 
of scales or bony plates; and the fore-limbs are so dispro- 
portionately small as compared with the hind-limbs, that this 
huge Reptile—like the equally huge Iguanodon—may be 
