PLATE 4 



EXPLANATION OF FIGURE 



5 Reconstruction of a 6 mm. Tragulus embryo. Collection No. 205. 

 X 100. Showing the arrangement of the axial venous channels. 1, aortic arches; 

 2, pre-cardinal vein, showing its horizontal and vertical limbs; 3, dorsal pre-car- 

 dinal tributaries ; 5, post-cardinal vein ; 6, umbilical vein ; 7. umbilical-post-cardinal 

 plexus; 9, omphalomesenteric vein; 10, duct of Cuvier; 11, sub-hepatic sinus; 

 12, sub-cardinal vein; IS, Wolffian duct; 14, Cloaca; 24, aorta. 



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