In the Gorilla, the vertebral column is similarly divided into cervical,
dorsal, lumbar, sacral, and coccygeal vertebrae, and the total number
of cervical and dorsal vertebrae, taken together, is the same as in
Man; but the development of a pair of ribs to the first lumbar vertebra,
which is an exceptional occurrence in Man, is the rule in the Gorilla;
and hence, as lumbar are distinguished from dorsal vertebrae only by
the presence or absence of free ribs, the seventeen "dorso-lumbar"
vertebrae of the Gorilla are divided into thirteen dorsal and four
lumbar, while in Man they are twelve dorsal and five lumbar.
FIG. 15.--Front and side views of the bony pelvis of Man, the Gorilla
and Gibbon: reduced from drawings made from nature, of the same
absolute length, by Mr. Waterhouse Hawkins.
Not only, however, does Man occasionally possess thirteen pair of ribs,*
but the Gorilla sometimes has fourteen pairs, while an Orang-Utan
skeleton in the Museum of the Royal College of Surgeons has twelve
dorsal and five lumbar vertebrae, as in Man. Cuvier notes the same
number in a 'Hylobates'. On the other hand, among the lower Apes, many
possess twelve dorsal and six or seven lumbar vertebrae; the
Douroucouli has fourteen dorsal and eight lumbar, and a Lemur ('Stenops
tardigradus') has fifteen dorsal and nine lumbar vertebrae.
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