HUBRECHT. (PULSE. 
Fig. Sa. Section through an early bat’s blastocyst (cf. Fig. 6 to 8); ¢# 
trophoblast; ez entoderm. The ectodermic shield has not yet emerged out of 
its trophoblastic covering (after van Beneden, 99). — Fig. 9. Seetion through early 
stage of the bat (after Duval) e& embryonic knob. ¢ trophoblast. — Fig. 10. 
Section through early stage of the shrew (after Hubrecht, ‘90). e& embryonic 
knob, ¢ trophoblast. — Fig. 11 and 12. Sections through early stages of the 
mouse, before and after fixation of the blastocyst to the uterine epithelium 2. — 
Fig. 13 and 14. Two sections through the embryonic knob of Cervus (after 
Keibel, 99) before and after the development of the entoderm by delamination. 
The trophoblast (¢~) is quite distinet from the embryonic ectoderm ec; in Fig. 13 
ectoderm and entoderm are yet united in the embryonic knob. 
