o£ Professor D. Wilson's Illustrations of the Significance 
on the mode of nurture in infancy, having tended, in their 
case also, if not to produce, to exaggerate the short longi- 
tudinal diameter, which constitutes one of their most re- 
markable characteristics. 
The idea thus expressed, in a paper read before the 
American Scientific Association at Montreal, as well as at 
the Dublin meeting of the British Association in 1857, was 
the result of observations made before leaving Scotland in 
1853. One chapter of the ‘“ Prehistoric Annals of Scotland” 
is devoted to a discussion as to the ethnological significance 
of the crania of Scottish tumuli; and after its publication I 
availed myself of every favourable opportunity for adding 
to the rare materials illustrative of that interesting depart- 
ment. In pursuing such researches my attention was re- 
peatedly drawn to the unsymmetrical proportions of ancient 
brachycephalic skulls, and to their peculiar truncated form, 
accompanied, as in the mound skull of the Scioto Valley, 
by an abrupt flattening of the occiput, which I soon began 
to suspect was due to artificial causes. Since then the 
facilities derived from repeated examinations of American 
collections have familiarised me, not only with the extreme 
varieties of form of which the human head is susceptible 
under the influence of artificial compression, but also with 
the less marked changes undesignedly resulting from such 
seemingly slight causes as the constant pressure of thé 
Indian cradle-board. The examination and measurement 
of several hundred specimens of American crania, as well 
as of the living head in representatives of various Indian 
tribes, have also satisfied me not only of the existence of 
dolichocephalic and brachycephalic heads as tribal or na- 
tional characteristics, but of the common occurrence of the 
same exaggerated brachycephalic form, accompanied with 
the vertical or obliquely flattened occiput, which had seemed 
to be characteristic of the crania of the Scottish tumuli. 
There are indeed ethnical differences apparent, as in the 
frontal and malar bones, but so far as the posterior region 
of the head is concerned, both appear to exhibit the same 
undesigned deformation resulting from the process of nursing 
still practised among many Indian tribes. 
The light thus thrown on the habits of the British 
