62 3IE. E. W. HOOLEY ON THE SKULL AND [Feb. I907, 



frontal aspect curtailed the arc of vision, and it would seem that the 

 creature's prey, or foes, were in an unobserved position when once 

 behind the orbits. 



In the greater length of the femur than of the humerus, and the 

 deep depression on the hinder extremities of the maxillae, which are 

 evidently the vestiges of preorbital vacuities, Goniopholis crassidens 

 is nearer the Teleosaurs than G. simus, but is farther removed than 

 the latter from them in the position of the posterior nares. 



Considering the massiveness of the head, and the weight which 

 its heavy armour must have given to the body, the length and 

 slenderness of the mandibles is remarkable. It is surprising how 

 they withstood the strain occasioned in a combat with, or the 

 capture of, the creature's more powerful congeners. 



The reptile was capable of a gape of over a metre. 



The presence of the interorbital keel, found in all the American 

 alligators, is probably the developed trait peculiar to a line descended 

 from the Goniopholidse. 



My thanks are due to Dr. A. Smith Woodward, E.R.S., for much 

 kindness and help in the preparation of this paper. 



EXPLANATION OP PLATES II-IV. 



Plate II. 

 Dorsal aspect of the skull of Goniopholis crassidens. ^ nat. size. 

 a = nasals ; b = maxilla ; c = lachrymal ; d — prefrontal ; e = frontal ; 

 f= postfrontal ; g = squamosal ; h = parietal ; i = jugal ; j = quadrato- 

 jugal; k — nasal passage; £ = orbit; m = supratemporal fossa; n= right 

 mandibular ramus ; = atlas ; p = axis ; £=lst& 2nd right cervical ribs : 

 r = distal end of ulna ; s = distal end of radius. 



Plate III. 

 Ventral aspect of the same. ^ nat. size. 

 a=palatine ; 6=pterygoid ; c=transpalatine ; cZ=occipital condyle; e=palato- 

 pterygoid vacuity ; / = posterior nares ; g = median eustachian canal ; 

 /i=dentary ; i =splenial ; j = angular. 



Plate IV. 



Pig. 1. — Eight lateral aspect of the skeleton of Goniopholis crassidens. 

 Yq nat. size. 

 a=lateral temporal fossa ; b = jugal and quadrato-jugal bar ; c = mandible : 

 d = 4th cervical vertebra ; e = 5th cervical vertebra ; / = 6th cervical 

 vertebra; g = portion of 7th cervical vertebra ; h = vertebral ribs ; 

 i == sternal ribs ; j = abdominal splint ribs k = ilium ; I = ischium ; 

 m = femur ; n = proximal end of tibia ; = distal end of tibia ; 

 p = dorsal scutes ; q = ventral scutes. 



Eig. 2. — Left lateral aspect of the same, yq nat. size. 

 a = external auditory meatus ; b = 3rd cervical vertebra ; c = dorsal ver- 

 tebras ; d = lumbar vertebras ; e = 1st sacral vertebra; /= sternal ribs ; 

 g — coracoid ; h = humerus ; i = ischium ; j = femur ; k = cervical 

 scutes. 



