Thomas Henry Huxley,
Quarterly Journal of the Geological Society of London
(1870)
“ A strong, prismatic sacral rib with a triangular section, only the proximal end of which remains, springs from the junction of the centrum with the neural arch on each side, in the first vertebra, and appears to have been directed perpendicularly outwards. The second vertebra seems to have possessed a similar rib, which, however, springs rather further back from the anterior edge of the arch. The third vertebra also possesses a strong rib, the root of which occupies the middle of the arch. The contour of the broken end of the rib is more nearly four-sided. ”
