THE DINOSAURIA. 
49 
Huxley and Mr. Hulke (see Fig. 1). Now when these skulls are 
critically compared with those referred to Belodon, some of 
which may belong to Zanclodon, the resemblance of plan 
is sufficiently close to arrest attention ; and points in which 
triassic skulls differ from Crocodilia are points in which they 
approach the Dinosauria. If the Crocodilian skull were sup- 
posed to be plastic and squeezed together from side to side, so 
as to become much narrower, and sufficiently elevated to make 
the eyes nearly vertical, then the chief point necessary to com- 
plete the Dinosaurian resemblance would be great relative 
enlargement of the cerebral cavity and the temporal fossae 
and a reduced length of the jaw. But if instead of comparing 
the Dinosaur with the living Crocodile, we had taken a repre- 
sentative of the fossil group of Crocodiles called Teleosauria, 
the resemblance would have been, with such modifications as 
suggested, almost perfect, nor would the palate have been so 
entirely incomparable with the Dinosaurian palate in certain 
Teleosaurs as in the existing Crocodile. These resemblances, 
however, are probably of value merely as showing that Dino- 
saurs and Teleosaurs may be descended from a common stock ; 
for as the Teleosaurs are unknown in the primary rocks, there 
is no reason for inferring that the one group was evolved from 
the other. The palate in Dinosaurs, so far as may be judged 
from its condition in Scelidosaurus and Hypsilophodon, finds its 
nearest parallel at the present day in the New-Zealand lizard 
Hatteria, in which the pterygoid bones have a similar form and 
send processes outward and backward to meet and lap along the 
inner processes of the quadrate bones, which articulate with 
the lower jaw, are similarly separated in the median line, and 
unite with comparatively slender palatine bones. It is difficult 
to estimate the importance of this and other resemblances which 
Dinosaurs show in the skull to Hatteria, especially since, 
taken as a whole, they do not counterbalance the remarkable 
resemblances to the Crocodilian group. Perhaps they rather 
indicate that the systematic place of Hatteria is nearer to 
Crocodiles than its earlier location among the Lizards might 
have suggested. The anterior nares are always placed well 
forward (Fig. 1), divided and almost surrounded by the pre- 
maxillary bones, much as in the Alligator. The nasal bones 
and frontal bones are elongated, as among Crocodiles, but it is 
not quite clear at present whether the frontal bone always 
enters into the cavity for the orbit of the eye. The frontal 
and parietal together contribute to form the large lateral sur- 
• faces behind the eyes, to which were attached the muscles 
which worked the lower jaw. At first sight this region offers 
some resemblance to Hatteria. The teeth vary in kind in dif- 
ferent Dinosaurs. Perhaps the most Crocodilian type is Mega- 
NEW SERIES, VOL. IV. NO. XIII. E 
