274 DAVIDSON BLACK 



recorded on the endocranial casts with certain additions, viz.: 

 1) the course of the meningeal vessels is usually reproduced with 

 minute detail; and 2) the grooves for the superior sagittal sinus 

 and its chief tributaries are evident, and by reason of the absence 

 of the falx cerebri the mesial boundary of the cerebral hemispheres 

 is not defined. On the adult cerebrum in no cases were small 

 sulci present that did not leave some impression (frequently 

 quite sharply defined) upon the corresponding endocranial sur- 

 face of the bone. This, however, was not always the case in 

 immature individuals. 



In adult carnivore skulls, especially in males, a considerable 

 amount of tentorial ossification occurs which increases with age. 

 Where the ossification is extensive the tentorium osseum retains 

 imprinted upon it the details of the fissural pattern of the ten- 

 torial surface of the cerebrum as well as that of the cerebellum. 

 In such specimens it was possible by casting separate cerebral 

 and cerebellar portions, or by breaking the cast along the ten- 

 torial plane, to obtain accurate information of the morphology 

 of the adjacent parts. 



In view of the greater minutiae of its detail, the cerebellar 

 morphology is usually not reproduced so clearly in an endocranial 

 cast as that of the cerebrum. The most important landmarks 

 of cerebellar morphology are, however, as a rule preserved. 



In contrast to endocranial casts, those of the endodural cavity 

 do not exhibit such sharpness of detail, and of course never show 

 any indication of the course of the meningeal vessels nor of the 

 grooves and vacuities for the venous sinuses. On the other hand, 

 the salient features of cerebral configuration along the line of the 

 great sagittal fissure are preserved and the line of demarcation 

 between cerebrum and cerebellum is sharply defined by the ten- 

 torium while in their general proportion and measurements the 

 casts more nearly accord with those of the corresponding brains. 

 It is thus possible to distinguish endocranial and endodural casts 

 with no possibility of confusion. 



It is evident that no cast can be one of the dural cavity which 

 shows upon its surface the detail of meningeal vessels, and irreg- 

 ularities corresponding to apertures such as the parieto-temporal 



