Plaie V. 



Arabic numerals placed between every two sections indicate the number 



of sections that intervene between those two (exclusive). 



Certain marks on the left of each section are for the identification of the 



sections and do not concern the reader. 



Series V. a-n. — Sections through an embryo of Chelonia caoiiana with 9 mesoblastic 

 somites, taken out 9^ days after deposition. Surface views given in 

 Figs. 5 (PI. I), 5a (PL II) and 5b (PL I). For detailed description see 

 p. 44. DDx2. (B 11 y>) 



Series VI. a-j. — Sections through an embryo of Trionyx jiqwniciis with about 10 

 mesoblastic somites, taken out S\ days after deposition. Surface view 

 given in Fig. 22, PL III— also similar to Coutiib. II, PL III, Figs. 19 

 and 19a). For detailed description see p. 48. CCx2. (143 ffl) 



Series VI. lon^. — Posterior portion of a longitudinal section through an embryo of 

 Trionijx japoniciis taken out from the same deposit at the same time as 

 that of the above series. DDx 2. (143 long.) 



The arrow indicates with its point the anterior end of the section. The 

 lines marked (j, h, i denote the planes through which the transverse 

 sections marked by the same letters pass through. 



