DETAILS OF EARLY EMBRYO. 



93 



Figs. 73 A-S. Transverse sections of embryo shown in plate V, fig. 38, and in plate VI. figs. 41 and 41 A. Thee begin at the 

 head end of the embryo, section A, and extend through 47 sections to the tip of the tail, section UU (see pages 94 and 95.) 



.'/' Gut cavity; 'I , nolochord ; 8, somite. 



