ON A UKS'I'ODK FROM CKSTRACION. 415 



Fig. 22. — Tliree-celled staE^e, 

 l*'iG. 23. — Four-celled stage. 

 Fig. 24.— Stage of about eiglit cells. 



Fig. 25. — Surface view of blastoderm of a somewhat later stage than that 

 represented in Fig. 24. 



Fig. 26. — Stage of about fourteen cells. 



Fig, 27.— Surface view of disc-like blastoderm. 



Figs. 28 and 29. — Disc-like stages seen edgewise. 



Fig. 30. — Hexacanth embryo with tiie hooks retracted. 



Fig. 31. — Hexacanth embryo with the hooks everted. 



Fig. 32. — Egg containing hexacanth embryo. Fresh specimen. 



VOL. 4G, TART 3. NI<;VV SKRIRS. C C 



