THE SKELETON 33 
Of special interest, however, are the variations of the separate 
divisions of the vertebral column, in relation to other parts of 
the skeleton which have become secondarily attached to it, such 
as the ribs and the pelvic girdle. These variations, though 
effected ontogenetically, have a phylogenetic significance, and 
tay therefore be described in further detail. 
Although the pre-sacral portion of the column consists normally 
of twenty-four vertebree, Embryology and Comparative Anatomy 
show that this cannot be regarded as a primitive condition, and 
that the pelvis formerly lay much farther back than at present, 
that is, that the trunk was originally longer than now. (We 
shall see later that a more extensive body-cavity or ccelom was 
connected with this greater length of the vertebral column.) 
Rosenberg has demonstrated that in the course of human 
development the first sacral vertebra becomes incorporated in 
the sacrum later than the second, and that later than the third, 
and so on. And further, since a primary relationship between 
the vertebree which become the two anterior coccygeal of the 
adult and the developing sacrum is discoverable, it is evident 
that while new sacral articulations are formed anteriorly, detach- 
ment of vertebre which were formerly sacral takes place 
posteriorly, the latter being transformed into coceygeal vertebree.’ 
A forward shifting of the sacrum and pelvic girdle is thus onto- 
genetically proved. 
attention to the detailed differences in the condition of the lumbar vertebre of the 
European and certain dark-skinned races, and the anthropoid Apes. ] 
[Cunningham has shown (Mem. R. Irish Acad., No. II. 1886) that Acby’s denial 
of the existence of a lumbar curvature in the Gorilla is untenable. His own test for 
a lumbar curvature is a line drawn from the centre of the anterior border of the 
upper surface of the first lumbar vertebra to the centre of the anterior border of the 
lower surface of the last lumbar vertebra. The distance of the most prominent 
point on the ventral surface of the lumbar section of the column from this line, 
multiplied by one hundred and divided by the length of the line, gives the index 
of curvature.] Little is known concerning the lumbar curvature of the savage 
races of mankind ; but the cousins Sarasin, on the examination of dried skeletons 
of the Veddahs of Ceylon, report the lumbar vertebre to be distinctly concave 
anteriorly. [From what has been said above, it would appear more than probable 
that the application of the Cunningham method to the study of the Veddah back- 
bone, in the fresh or specially prepared state, would reveal a lumbar curvature accord- 
ing to the above, its most recent and rigid, definition. And, from what is known of 
the backbones of other races (ex. the Australian), it would appear probable that 
the observation of the Sarasins is rather indicative of a greater suppleness of the 
column during life, induced by habitual resort to certain postures, such as squatting, 
which lead to a greater compression of the vertebre, and a corresponding greater 
tendency towards obliteration of the curvature after death. ] 
! Distinct indications of a shifting of the pelvic girdle are traceable in the lower 
animals also, such shifting being in some cases in a proximal and in others in a distal 
D 
