Note 21 — Chapter II · GENERAL ANATOMICAL CHARACTERS (continued 3)
Reading edition
For a full exposition of the present state of knowledge on this subject, see the various memoirs of Sir William Turner, also F. M. Balfour’s Treatise on Comparative Embryology, vol. ii. (1881), and J. A. Ryder in American Naturalist, vol. xxi. p. 780 (1887).