164 



suture between the maxillary and premaxillary bones : this extends in the present specimen 

 irregularly, but transversely, from behind the small foramen on the inner side of the mar- 

 ginal notch receiving the canine of the lower jaw ; whilst in the Cr. biporcatns the same 

 suture inclines from this point obliquely backwards, before it bends inwards to meet the oppo- 

 site half of the suture at the median line. The palatal processes of the premaxillary bones 

 are consequently relatively longer in the Cr. biporcatus, and the anterior palatal aperture of 

 the bony nostril is more nearly in the centre of the palatine plate of the premaxillaries in the 

 Cr. rhombifer. The posterior palatal aperture of the nostrils is not so completely marginal 

 in its position, and its plane is more horizontal in the present specimen. The right lateral 

 eustachian canal has been laid open as far as the tympanum, and a portion of wire is passed 

 through the median eustachian canal, to show the communication of its lateral basioccipital 

 branch with the lateral eustachian canal. The left carotid canal is laid open and a bristle is 

 passed through it into the tympanic cavity, and into the canal continued to the sella turcica 

 in the cranial cavity. The number of alveoli is in the premaxillary, 5 4 ; in the maxil- 

 lary, 14 14 ; in the dentary, 15 15. The specimen is from Bengal. 



Presented by Dr. Nathaniel Wallich, F.E.S. 



751. The skull of a larger individual of the Crocodilus rhombifer. 



Like the preceding specimen, it differs from Cr. biporcatus in the greater breadth of the 

 maxillary and premaxillary portion of the skull. The palatine suture of the premaxillary 

 bones is likewise transverse. The posterior palatine vacuities are broader in proportion to 

 their length, and the palatine bones are narrower. There is a smaller proportion of the ecto- 

 pterygoid behind the last alveolus. The teeth are larger in proportion to the length of the- 

 skull. The antorbital ridges are not continued so far forwards. The number of the alveoli is 

 in the premaxillary, 5 5 ; in the maxillary, 14 14 ; in the dentary, 14 15. 



Presented by B. C. Henderson, Esq., F.R.S. 



752. The skull of a Crocodile from Bengal, wanting the lower jaw, of a species (Cro- 



codilus palustris ?) which is frequently found inhabiting the larger ponds. It 

 differs from the Cr. biporcatus of the Ganges in having shorter maxillary and 

 premaxillary bones in proportion to its length, in having much less developed 

 prefrontal ridges ; the palatal suture between the maxillary and premaxillary 

 bones is transverse, not curved. The anterior extremities of the palatine bones 

 are narrower and more pointed. The number of the alveoli is, premaxillary, 

 5 5 ; maxillary, 14 14. 



753. A longitudinal section of the left ramus and teeth of the lower jaw of a young 



Crocodile, showing the pulp-cavities of the teeth in place and the germs of 

 their successors. 



