MEASUREMENTS OF THE CRANIAL FOSS^. 



By Ales IlKDLirKA, 



Asmstant Caratur, Division of I'hi/fiical AuthropoUxjij, V. S. yational Miixrui 



While there exists only a g'eneral correlation between the outside 

 and the inside of the skull, the brain and the cranial cavity correspond 

 under normal conditions exactly. The brain is separated from the. 

 skull onl}" by the meninges, which, however, are of small and uniform 

 thickness, and adhere eyerj'where closely to the organ as well as to the 

 bone, so that the above statement is not affected. 



The skull cavity presents certain subdivisions, known as cranial fos- 

 sje, which correspond with certain portions of the brain. These fossa^ 

 are termed the anterior, middle, and posterior, and the parts of the 

 ))rain they inclose are the anterior, middle, and posterior lobes of the 

 cerebrum, with the cerebellum. The two last named occupy the pos- 

 terior fossa on each side, one its superior and the other its inferior 

 portion. As the study of the brain is continually gainino- in impor- 

 tance, one of the most valuable investigations on this organ would be a 

 series of accurate measurements of its lobes; ))ut the lirain is soft, and 

 before it can be measured must be hardened in preservatives. This, 

 in the case of the heavy human ])rain, is seldom achieved without some 

 flattening or other deformation. Measurements on a deformed organ 

 can, however, never be accurate and can not be relied upon for any 

 liner differentiations. Moreover, normal human brains are not easily 

 obtained, even those of the whites, and in the case of many races, in 

 which the study of the organ is most urgent, the material is extremely 

 limited or wholly wanting. As a good example of this may be cited the 

 North American Indian, whose brain has never yet been properly 

 studied. There are now in the U. S. National Museum just three brains 

 of these people, and all of them are so badly deformed or damaged as to 

 be entirely unsuitable for measurement. Under such circumstances, 

 and in view of the close correspondence of subdivisions of the brain 

 with those of the skull cavity, it becomes desirable to utilize, so far as 

 feasible, measurements on the latter and on its subdivisions. This has 

 been attempted b3^the author, and the present report is the result of a 

 limited number of the more important measurements. 



Proceedings U. S. National Museum, Vol. XXXIl— No. 1 521 - 

 Proc. N. M. vol. xxxii— 07 12 177 



