214 EEPORT OF NATIONAL MUSEUM, 1887. 



parage alike the methods and the results of anthropological research 

 in certain directions, but they neither obviate the necessity of initiating 

 further study from existing information, nor impugn its value as a whole. 



In considering the natural history of the human head, account must 

 be taken of the fact that man, while not alone in this respect, is never- 

 theless an exceedingly aberrant form among the Mammalia. On any 

 theory of life, however, except that of special creation, and independ- 

 ently of conflicting estimates of the systematic implications of structure, 

 the organization of this most highly specialized being must be regarded 

 as the outcome of descent, with modification, and should therefore be 

 considered in connection with that of the groups to which man is affil- 

 iated. 



As has been said, there is no absolute form for the head or for the 

 vertebrae of which it is composed, and the fact that all classifications 

 resting upon its features have failed, does not encourage the hope that 

 the results sought through craniometry will be attained by means of its 

 descriptive anatomy. All that can be properly affirmed is, that during 

 the immemorial series of adjustments by which the mammals culmi- 

 nated in man, and in which evolutional changes of all orders are in- 

 cluded, the human head assumed an incompletely distinctive form, which 

 is, both in itself and in the causes which determine its variations, more, 

 or less clearly revealed in the tribal history of mankind. The state- 

 ment that the anthropoid head becomes less human with development 

 has been generally united with the assumption that this implies im- 

 portant generic differences between them, and if the observation were 

 true in the sense in which it is for the most part understood, it would 

 do so. Its special significance is, however, detracted from by the gen- 

 eral truth that in zoology the rule is that, for obvious reasons, young, 

 creatures are less differentiated than those which are mature ; while, 

 on the other hand, the difficulty of discriminating between the adult 

 brains of some of the higher apes and those of certain savages, may be 

 considered as qualifying the former assertion to so great a degree as to 

 suggest error, or at least inexactness, in the observation. Bo doubt 

 the mistake is partially attributable to misconceptions arising from an 

 idea of the fixity of species, but in itself, the error is involved in all 

 comparisons between unlike things. To found a parallel upon the ex- 

 ternal tables of the skull, as if these were equally characteristic and 

 similarly developed in a gorilla and a man, is to include in the terms 

 dissimilar elements, and thereby vitiate the comparison. The contours 

 of the head in these instances are differently related, and, considering 

 the plates of the skull especially, the external table of the ape's cra- 

 nium is much more prominently associated with the muscular appar- 

 atus than is the case with man, in whom the subordination of the en- 

 tire head to the encephalon is exceptional. This is but a single illus- 

 tration of the general fact that throughout the vertebrate class the cra- 

 nium proper, amid innumerable subordinate variations, assumes the 



