Con.Art. 



('on Art 



.pnk^ 



Fig. 5 Rabbit, 9 days, 8 segments, 3.2mm., H.E.C. no. 621. Reconstruction of 

 the blood-vessels of the head end of the embryo; seen as though looking forward 

 from the anterior end of the lateral hearts, to show network for first arch. Ao.d., 

 dorsal aortae; Con. art., conns arteriosus; IV.. lateral hearts; Ao.d., network for 

 ventral aorta; y, extension toward median line; x, blind ends of obliterated ves- 

 sels from yolk-sac. X 125. 



Fig. 6 Rabbit, 9 days, 8 segments, 3.2 mm., H.E.C. no. 709. Reconstruction 

 and lettering similar to those in tig. 5. At y the extension of the ventral aortic 

 network lias fused with that of the other side. X 125. 



Fig. 7 Rabbit, 9 days, 11 segments, 3.8 mm., H.E.C. no. 619. Reconstruction 

 and lettering similar to th ise of fig. 5. Ar.l . Ar.2, first and second aortic arches. 

 X 125. 



121 



