132 COMPARATIVE ANATOMY chap, ii 



Literature. 



E. Haeckel. Die Gastrula und die EifurcJiung, in : Jenaische Zeitschrift. Bd. 

 IX. 1877. 



F, M. Balfour. Comparatim Embryology. 2 vols. London, 1880-81. 



A. C. Haddon. An Introduction to the Study of Embryology. London, 1887 (Tr.) 

 Compare fiu'ther the bibliogi-apliy on p. 117. 



