148 ILLUSTRATIONS OF THE SIGNIFICANCE OF 
tored nomades subject their offspring to many artificial’ influences, 
such as have no analogy among the marvellous instinctive operations 
of the lower animals. It is not even unworthy of notice that man is 
the only animal to whom a supine position is natural for repose; and 
with him more than any. other animal, the head when recumbent, 
invariably assumes a position which throws the greatest pressure on 
the brain-case, and not on the malar or maxillary bones. Without, 
therefore, running to the extreme of Dr. Merton, who denied, for the 
American continent at least, the existence of any) true dolichocephalic¢ 
crania, or indeed any essential variation. from one assumed. typical 
form, it becomes an important point for the craniclogist to determine, 
if possible, to what extent certain characteristic diversities may be 
relied upon as the inherited features of a tribe or race; or whether 
they are not the mere result of artificial causes originating in long 
perpetuated national customs and nursery usages. If the latter is 
indeed the case, then they pertain to the materials of archeological, 
rather than of ethnological deduction, and can no longer be employed 
as elements of ethnical classification. 
Every scheme of the craniologist for systematising ethnical 
variations of cranial configuration, and every process of induction 
pursued by the ethnologist from such data, proceed on the 
assumption that such varieties in the form of cranium are constant 
within certain determinate limits, and originate in like natural 
causes with the features by which we distinguish one nation from 
another. By like means the comparative anatomist discriminates 
between the remains of the Bos primigenius, the Bos longifrons, and 
other kindred animal remaiis, frequently found alongside of the human 
skeleton, in the barrow: and by a similar crucial comparison the 
craniologist aims at classifying the crania of the ancient Briton, Roman, 
Saxon, and Scandinavian, apart from any aid derived from the evidence 
of accompanying works of art. But if it be no longer disputable that 
the human head is lable to modification from external causes, so that 
one skull may have been subjected to lateral compression, resulting in 
the elongation and narrowing of its form; while another under the 
influence of occipital pressure may exhibit a consequent abbreviation in 
its length, accompanied by parietal expansion ; it becomes indispen- 
sable to determine some data whereby to eliminate this perturbing 
element before we can ascertain the actual significance of national skull- 
forms. If, for example,—as appears to be the case,—the crania from 
British graves of Roman times reveal a different form from that of 
