86 



only one millimetre. This effect may, in some degree, be due 

 to distortion. 



To give a more detailed account of the several elements 

 of the skull, we take up first the basioccipital. This bone is 

 remarkably long and straight, tapers gradually downwards, 

 and becomes quite narrow at the distal end. It is smooth 

 throughout, and exhibits no rugose muscular attachments, 

 such as are sometimes seen in other members of the order. 

 The condyle is large and nearly spherical, but with median 

 groove distinctly marked. In size and shape it is more like 

 that of the alligator than of the ordinary crocodile, but it is 

 somewhat different from either. It differs from the former, in 

 not having so loag a neck distinctly marked by a constriction ; 

 and from the latter, in not having additional articular faces on 

 each side of the condyle proper. As far as can be judged, no 

 portion of it is formed by the exoccipitals. Below the con- 

 dyle, the basioccipital is perforated by two small vascular 

 foramina ; the spheno occipital canal occupies the usual place, 

 and is very large. 



The exoccipitals are large, of very great width, but rather 

 low from above downwards. The position of the foramina 

 which perforate these bones is peculiar ; it resembles more 

 the arrangement seen in the skull of the alligator than in that 

 of the crocodile, but it has an additional foramen. There are, 

 then, two small venous foramina near the condyle ; while 

 along the lateral margin of the occiput, are placed in a verti- 

 cal line the foramina for the hypoglossal and pneumogastric 

 nerves, and the internal carotid artery. The foramen for the 

 facial nerve, etc., is situated in the usual place, and is of the 

 usual size. The foramen magnum is heart-shaped, low, wide 

 above, contracting below. The paroccipital processes are 

 long and slender, and project strongly backwards. 



The supraoccipital is very small. It shows to some extent 

 on the upper surface of the skull, wedged in between the pa- 

 rietals. As a whole, the occiput is of remarkable shape : it is 

 perfectly vertical, as in all other crocodilians ; is remarkably 

 high from above downwards, and is very broad at top, becom- 

 ing extremely narrow distally. This latter feature is owing 

 to the peculiar shape of the pterygoids ; which, when viewed 

 from behind, do not appear to reach the basioccipital. 



