106 Walter E. Dandy. 
PLATE III. 
Ic. 12. Diagram of a sagittal view of embryo to show the vascular system. 
Ht, Heart; A I-II-III, First, second and third aortic arches; Ao, Dorsal aorta ; 
C.Ao, Caudal aorta; U, Umbilical artery (unite in the bauchstiel) ; V, Um- 
bilical vein (unite in the Bauchstiel) ; Vit, Branch of umbilical vein, is only 
suggestion of a possible vitelline vein; V. am, Venous branch to amnion; Ca, 
Capillaries; do not contain blood and do not connect with veins; B.I., Blood 
Islands; Ect, Ectoderm; Mes, Mesoderm; Ent, Entoderm; Fg, Foregut; Hg, 
Hindgut; All, Allantois; Ch, Chorionic membrane; V1, Chorionic villi, showing 
vascularization; B.S, Bauchstiel; M.C., Mouth Cavity. 
