ii Plate i. 



the median line over the mid-dorsal region, but diverge both anteriorly 

 and posteriorly. The medullary canal is still open at the posterior 

 darkened place. See p. 21. Sections given in Series V (PI. V). 

 f/rtX2. (Bli^N) 



Fig. 5è. — Dorsal view of the posterior part of the same embryo under greater 

 magnification. AAx2. 



Fig. 6. — Dorsal view of the posterior part of another embryo taken out from the 

 same deposit at the same time as that represented in Fig. 5. See p. 22. 

 .^.4x2. (B lia) 



YiG. 7. — Dorsal view of an embryo of Chelonia caouana taken out 14 days after its 

 deposition. The amnion leaves only the small posterior portion of the 

 embryo exposed. The extra-embryonic cœlomic cavities touch each other 

 in the median line over the anterior two thirds of the dorsal region, but 

 diverge towards the posterior portion. See p. 23. aa x 2. (A 8 -f ) 



Fig, 8. — Dorsal view of an embryo of Chelonia caouana, with about 16 mesoblastic 

 somites, taken out lOi days after its deposition. The amnion has not 

 only covered the embryo, but extended itself as a tube some distance 

 behind it. The extra-embryonic cœlomic cavities diverge from each other 

 towards the posterior end of the embryo. See p. 24. Sections in 

 Series IX (PI. VII). aa x 2. (B 12 -f ) 



