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and forms in the back part a large oval hole. The angular bone 
curves upwards, to occupy a space in the inside of the jaw. Between 
this bone and the opercular is another oval hole, smaller than the 
preceding ; and above that a void, in consequence of the coronoidal 
not turning towards the inner surface : the anterior point of this space 
is bordered by a small bone of a crescent form. The condyle, all the 
superior surface of the posterior apophysis, and all the internal surface 
of this part, belongs to the articular bone. In the crocodile there is 
no sensible coronoidal apophysis. 
The lower jaw of the monitor is composed of the same number of 
bones as in the crocodile ; but, in the monitor, the angular is much 
shorter and narrower, and the coronoidal terminates as if truncated, 
where it unites with the dental ; the large oval hole not being left 
between them, which is observed in the crocodile. The coronoid 
apophysis is formed by the bone which, in the crocodile, is termed 
the crescent bone. The articular bone alone forms the posterior 
apophysis ; and joins, with its internal surface, the crescent, and 
carries to the upper edge of the bone the opening for the entry of the 
maxillary nerve, which opening is so large in the crocodile. In the 
monitor, also, there is no opening in the inner surface between the 
opercular and the angular bone ; but there is a small one in the oper- 
cular itself, and a larger one between that bone and the dental. 
In the lower jaw of the animal of Maestricht, of which the coronoidal 
apophysis is seen at s, the angular bone at t, and the dental at u and 
y, there is no large oval hole in the external surface ; the coronoid 
process is a distinct bone, analagous with the crescent-formed bone ; 
the articular bone alone forms the posterior apophysis, and disposes 
the angular much forwarder ; the coronoidal unites with the dental 
bone in a straight transverse suture ; and there exists a small opening 
in the opercular bone. 
This animal, therefore, approaches the nearest to the monitor, 
nearer even than to the iguana, in the conformation of the lower jaw, 
