1 9© I.] Matthew, Additional Observations on the Creodonta. 3^ 



Zygomatic process of the squamosal moderately stout, as in 

 Periptychus, placed well back on the side of the skull (its anterior 



Fig. II. Triisodon heilprinianus. No. 764. Side view of skull, one-half natural size. Outline 

 of occiput from No. 3181. 



edge one fourth the skull-length from the occipital condyle) as in 

 Mesonyx. In Arctocyon it is placed further forward, besides being 

 more massive, reducing the length of the zygomata, which are 

 increased in width though not proportionately. 



The postorbital process on the frontal appears to have been 

 less developed than in Mesonyx ; on the malar it appears to have 

 been absent. The postorbital constriction of the skull is very 

 marked, as much so as in Arctocyon, more than in Mesonyx or 

 Periptychus. 



Fig. 12. Triisodon heilprinianus^ No. 764. Upper dentition, crown view, natural size. 



The occipital bones seem to have been firmly sutured together, 

 breaking away rather easily from the rest of the skull. 



