Very rare undistributed second and final part of beautiful bird plates (XI-XX) for the series Symbolae physicae by the German zoologist Christian Gottfried Ehrenberg (1795-1876). The large plates, beautifully coloured by hand, show birds from northern Africa and the Middle East. They are shown perched on branches, many surrounded with detail drawings of bills and feet. They were drawn by Wilhelm Müller and Friedrich Bürde and executed by Bürde, Elsasser, Pohlke and Schmidt.This monumental work on animals, and later also plants, from Africa and the Middle East was published in parts, the original series from 1828 to 1845 covering mammals, birds, insects and other invertebrates, giving 90 plates in total. Additional parts covering other kinds of animals (32 or 34 plates) and plants (24 plates) appeared in 1899 and 1900. The literature describes the present work as unfinished, but the ten additional bird plates were in fact printed, though never distributed.
Printed on fine wove paper and in very good condition, wholly untrimmed and in the original printed portfolio. Cf. Fine Bird Books, p. 74; Junk, Rara, p. 138; Nissen, IVB 290; Wood, p. 330 (all lacking these 10 bird plates); not in Anker.