Drawing, vertebrae of the spines of birds by unknown artist Plate 30 containing six figures of spinal vertebrae showing articulation. The work is inscribed with publication and plate details. Not signed. Royal Society stamp verso. Watermarked '[Turk]ey Mills [J Wh]atman 1820'. The manuscript for this paper is wanting. Subject: Physiology Published in Philosophical Transactions as part of paper titled 'On the mechanism of the spine' by Henry Earle. Read to the Royal Society on 25 April 1822. [1822]