50 K. MITSUKURI. 



Fig. 71a. Ventral view of the same. 



A low lobate process of the membranes situated close 

 to the left of the tri-radiate allantoic seams penetrates 

 into the mass of the white. 



Fig. 72. Surface view of a Tri onyx embryo 15f days old. X 5^. 



(1-7.) 



This corresponds to Fig. 67. of Clemmys, and the ex- 

 planation of the latter is applicable to this. The 

 white line stretching from the neck of the embryo to 

 its posterior end is the sero-amniotic connection. Its 

 slight posterior expansion marks the remnant of the 

 posterior tube of the amnion. 

 Fig. 73. Embryo represented in Fig. 26. with the yolk-sac and the 



foetal membranes. Blood-vessels on the yolk-sac omitted. 



Slightly enlarged. ^^^^'^ 



Fig. 74. Ventral view of a Trionyx embryo 42 days old with the 



yolk-sac and the foetal membranes. Slightly enlarged. 



(ISl.) 



Plate. IX. 



Fig. 76. Blood-vessels that pass through the umbilicus. 

 Fig. 76. Part of a transverse section through the sero-amniotic 

 connection of a Clemmys embryo 13 days old. DD x 4. 



(LIX.) 



Fig. 77. Diagram of the region of the posterior tube of the Amnion. 



Figs. 78-80. Selected transverse sections through the posterior part 

 of the sero-amniotic connection and the remnant of the 

 posterior tube of the Amnion in the Clemmys embryo 

 represented in Fig. 71. CC x 2. 



