58 MR,. E. \V, H00LEY ON THE SKULL AND [Feb. I907, 



IY. Agreement of the Atheefield Fossil with the Type- 

 Specimen OF GONIOPHOLIS CRASSIDENS. 



As previously noted, the impression of the skull on the slab 

 containing the type-remains had never been described. Further, it 

 has been seen that the known portions of the skull of Goniopholis 

 crassidens consist of teeth and part of the left mandibular ramus ; 

 for the fragments of the mandibles described and figured by Owen 

 were, as before stated, apparently referred to this species because 

 they were discovered on the same geological horizon. With the 

 ramus, teeth, and odd bones of the type, the Atherfield fossil agrees. 

 The impression of the cranial surface on Hantell's slab begins 

 near the position of the parieto -frontal suture, and embraces the 

 outline of the anterior moiety of the left supratemporal fossa 

 and portions of the pre-frontals, lachrymals, nasals, and maxillae. 

 No trace of the sutures of these bones is to be found, and so their 

 form cannot be determined. The anterior outline of the orbits can 

 be fairly judged. 



So far as can be ascertained, the orbits longitudinally and trans- 

 versely, and the measurements of the impression of the left inner 

 anterior corner of the left supratemporal fossa, agree with the 

 Atherfield skull. The sculpturing, the contours of the orbits, the 

 slightly-concave interorbital space, and its elevation as it nears the 

 orbital rim, likewise are close to that of the Atherfield cranium. 



With the impression was a fragment of bone, across the inter- 

 orbital tract, near the position where the keel noted in Goniopholis 

 simus occurs. It seemed possible that its presence might be due to 

 a similar ridge having given an extra grip on the matrix. 



On my calling Dr. A. Smith Woodward's attention to this possi- 

 bility, he deemed it important enough to have the fragment removed, 

 with the result that no keel was discovered, but a concave pitted 

 surface as in the Atherfield skull. 



From these considerations I have no hesitation in assigning the 

 Atherfield remains to Goniopholis crassidens. That being so, I shall 

 endeavour to demonstrate that the skull of G. crassidens differs in 

 many important particulars from that of G. simus and other Gronio- 

 pholidse, and hereafter shall refer to it as Goniopholis crassidens. 



V. COMPARISONS BETWEEN THE SKULLS OF GONIOPHOLIS CRASSIDENS 

 AND G. SIMUS. 



(1) In its dimensions the skull of G. crassidens is a third greater 

 than that of G. simus. The general outline is similar. 



(2) In G. crassidens the supratemporal fossae are twice the size 

 of the orbits, in G. simus only slightly larger. 



(3) In G. crassidens they are subcircular, but subquadrate in 

 G. simus. 



(4) Deep pre-orbital depressions exist on the maxillse of G. cras- 

 sidens; mere traces in G. simus. 



