186 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXXII. 



It is seen that throughout, in adults, the relatively longer anterior 

 fossjB correspond to smaller skulls, and the opposite. The Indian and 

 negro, and the sex, are no exception; apparently the phenomenon is 

 general in the whole human famil}*. Individual cases not agreeing 

 with the rule were met with in all the groups, but were not very 

 numerous. The inmiediate cause of the condition, upon which more 

 light will be thrown in later paragraphs, can only be a slightly less 

 capacity, or rather necessit}', of growth in length of the frontal fossse 

 than that of growth in length of the rest of the cranium. This can 

 in all probability be applied also to the growth of the frontal lobes 

 of the cerebrum, an indication of a relatively greater expansion of 

 the other portions of the organ, containing the motor and sensory 

 areas, in the course of development. 



It remains to consider the proportions of the anterior fossae in adults 

 and young, men and animals, sexes, races, and different cranial forms. 

 For these purposes the mean length of the two fossae may be compared 

 again with the greatest external cranial diameter. The following 

 table presents in a succinct form the results. Only those skulls are 

 here included in which both fosste could be measured, which removes 

 some possible causes of error. 



Lengfit jiroportions of anterior fossse in relation to greatest external length of the skull. 



Subjects. 



Num- 

 ber of 

 skulls. 



Average 

 external 

 maxi- 

 mum 

 length of 

 skull. 



Average Average relation 



mean 

 length of 



the 2 

 anterior 



fossse. 



of the length of 

 the fossffi to the 



dorsal length 

 of the skull, 



and extremes. 



Adults: 



Whites, males — 



Dolichocephals 



Mesocephals 



Brachycephals 



Whites, females — 



Dolichocephals 



Mesocephals 



Brachycephals 



Indians, males — 



Dolichocephals 



Brachycephals 



Negroes — " 



Males, dolicho- and mesocephals . . . 



Females, dolicho- and mesocephals. 

 Fetuses and young: 



White fetuses and children, brachycephals 

 Colored fetuses and children : 



Brachycephals 



Dolicho- and mesocephals 



Anthropoid apes: 



Chimpanzees 



Orangs 



Gibbons 



Monkeys and lemurs: 



Mncnrii<< prli}iis 



Ohii.< Injiiiilt ni'us 



Aloiiiild .^( iiiculd. 



Midas 



Lemur varius 



C7n. 

 19.4 



18.7 

 18.2 



17.8 

 17.8 

 17.3 



IS. 3 

 l(i.9 



IS.G 

 17.7 



11.9 

 11.0 



7.6 



7.0 

 4.1 

 6.0 



mm. 

 52.7 

 61.5 

 49.8 



48.2 

 49.7 

 48.6 



46.6 

 45.4 



50.6 

 50.1 



39.0 

 36.2 

 27.3 



29.5 

 23.2 

 23.0 

 13.0 

 22.0 



27.2 (25.3-28.8) 



27.5 (24.3-30.2) 



27.3 (24.5-30.9) 



27.1 (24.6-30.6) 



28.1 (26.1-30-6) 



28.2 (25.6-31.2) 



25.6 (22.7-29.6) 

 26.8 (24.4-28.6) 



27.3 

 28.3 



25.3-30.7) 

 '26.2-30.2) 



31.1 (28.6-35.0) 



30.9 (27.5-35.7) 

 30.6 (26.1-35.6) 



32.9 (31.4-34.0) 

 30.4 (28.2-32.8) 



36.2 (35.0-37.3) 



36.0 

 30.0 

 32.9 

 31.7 

 36.7 



The above data certainly reveal interesting conditions. 

 The relative length of the anterior fossae is in general decidedly 

 greater in fetuses and 3"oung than in adults; the antero-posterior 



