LTASSIC CROCODILES. 133 



the orbital margin of tlie malar is not raised, and does not leave behind it a deep 

 fissure as in the Gavial. The malar does not rise to join the postfrontal at the level 

 of that bone, but this descends to join the malar at the external margin of the orbit. 

 The vacuity between the orbit and mastotympanic is much elongated in the fossil, 

 and occupies four fifths of the temporal fossa ; the anterior part of this fossa is 

 narrow and acute. The columella or ossicle of the ear is cyhndrical, and much 

 larger in proportion than in any known Crocodile or other reptile. 



Cuvier calculates the number of teeth in the Teleosaurus Gadomensis to be 180, 

 viz. ffzl-f-. The Teleosaurus Ghapmanni has at least 140 teeth. The Gavial has 



IIZ, or 28-28- 



The teeth of the Whitby Teleosaur are as slender and sharp-pointed, but not so 

 compressed, as in the Gavial ; they correspond with those of the Caen Teleosaur, 

 and equally illustrate the dental characters usually attributed to the present extinct 

 genus. 



The Whitby Teleosaur differs from the Caen Teleosaur, as does the Monheim 

 Teleosam-,^ in having the upper temporal fossse longer in proportion, to their 

 breadth ; but it differs from the Teleosaurs of both Caen and Monheim in the more 

 equal size of the teeth, and from the Monheim species in the greater number of 

 teeth, the Teleosmirus loriscus having at most f|z|-|=106. The median frontal in 

 the Whitby Teleosaur is slightly concave, in the Caen species it is flat. The basi- 

 occipital is perforated by the common terminal canal of the Eustachian tube close 

 to the junction with the sphenoid, and on each side of the hole it expands into a 

 rough tuberosity. The body of the sphenoid is compressed, characterised by two 

 processes or narrow ridges, continued one from each side of the middle of the 

 sphenoid obliquely backwards. The pterygoid bones are relatively smaller than in 

 the Gavial. The palatine bones are more extended postei'iorly, and articulate with 

 the transverse bones. The posterior apertures of the nasal canals are placed more 

 forwards upon the base of the skull than in existing Crocodiles. 



Vertebral Golumn. — The number of vertebrse in the true Crocodiles of the 

 present period rarely exceeds sixty, which is the number originally assigned by 

 ^lian to the spinal column of the Crocodile of the Nile. Cuvier generally found 

 7 cervical, 12 dorsal, 5 lumbar, 2 sacral, and 34 caudal vertebrge. 



In the Crocodilus aaitus a thirteenth pair of ribs is occasionally developed, and, 

 according to Plumier, it has two additional caudal vertebrge. 



The Alligator {Alligator Lucius) has 68 vertebrse, the additional ones being 

 in the caudal region. 



The Gavial has 67 vertebra?, disposed as follows: — 7 cervical, 13 dorsal, 

 4 lumbar, 2 sacral, and 41 caudal vertebrae. 



The more perfect specimen in the Whitby Museum displays the number of the 



1 Crocodilus priscus, Soemmerring. 



