ox THE FOETAL MEMBRANES OP CHELOXIA. 



51 



Fig. 78. Through the line 1-1 in Fig. 77. 



Fig. 79. „ „ „ 2-2 in Fig. 77. 



Fig. 80. „ „ „ 3-3 in Fig. 77. 



Fig. 81. Region on the non-embryonic pole of the yolk-sac where 

 the allantoic lobes meet. From a Trionyx embryo similar 

 to Fig. 74. Seen from outside the serous envelope, x 3. 



(182.) 



Fig. 81a. The same region seen from inside. 



Figs. 82-85. Selected sagittal sections through the region repre- 

 sented in Figs. 81 and Sla. aa x 2. 

 Fig. 82. is to the extreme left of Fig. 81a. and the sections 

 gradually proceed toward the right. 

 Fig. 84a. Region of the sero-amniotic connection in Fig. 84. more 

 highly magnified. DD x 2. 



Plate. X, 



Fig. 85. Transverse section from the head-region of the Clemmys 



embryo represented in Fig. 11. aa x 2. 

 Fig. 86. Similar section from the head -region of a Clemmys embryo 



13 days old. aa x 2. *""* 



Fig. 87. Longitudinal section of a Trionyx embryo 16 days old 



(the same embryo as that given m Fig. 2'1). CG x 1. ' '■'> 

 Fiq. 87a. Transverse section through the allantoic vesicle of an 



embryo of the same stage. CC x 1. 

 Diags. I~VII. Give a summary of the development of the fœtal 



membranes in Chelonia. 

 Diags. I-V. Applicable to both Clemmys and Trionyx. 

 Diag. I. Corresponds to Fig. I. (PI. I.) and to Fig. 



