view of the vicinity of their sero-amniotic connection. The allantoic septa of 

 Fig. 15 shonld he examined along witli the hlood vessels represented in Fig. 

 14 : — a fall description of them is given in tlie text. The areas of the amnio- 

 tic cavity and of tlie albumen-sac are represented by dotted lines, but a part of 

 the yolk-sac is concealed beneath the albumen-sac. In Fig. 16, the albumen- 

 sac is advanced as a cave-like diverticulum, GPKL, towards the amnion, 

 which it meets along the line KP. the sero-amniotic connection. The 

 area UE"E'CHCtDF'E" is a part of the iuterallantoic septum, Avhich is 

 folded along the line DP7'. The sero-amniotic connection is represented 

 isolated in Fig. 49. 



Figs. 17-18 : — The first is a diagrammatic representation of the allantoic septa alone, 

 and the second of all the foetal membranes of the egg represented in Figs. 14 

 and 15. In both, the outer allantoic limb is removed to a great extent. In 

 Fig. 17 the folded area FEDGrHGE is a part of the iuterallantoic septun]. The 

 line ED is the axis along which the iuterallantoic septum is folded in two. The 

 area ABC is the minor septum formed by the left allantoic artery. The septum 

 formed by the right allantoic artery is not represented. The deep black 

 areas represent duplicated parts of the septa. The positions of the albumen- 

 sac, the yolk-sac, the umbilical stalk, and the amniotic cavity are shown by 

 artificial incisions. In Fig. 18 the areas of the anniiotic cavity and albumen- 

 sac are given in addition, but a part of tlie yolk-sac is concealed beneath 

 the cave-like diverticulum of the albumen-sac. 



Figs. 19-21 : — Fig. 19 is a surface view of an egg, 264 hours old, taken out from 

 its non-cellular envelopes. Fig. 20 represents the outlines of the foetal 

 membranes ; Fig. 20 bis the minor septa formed by the right allantoic artery 

 as seen from the surface ; and Fig. 21 the surface view of the vicinity of the 

 sero-amniotic connection. In examining the allantoic septa of Fig. 20 re- 

 ference should be made to the blood vessels represented iu Fig. 19. The 

 areas of the amniotic cavity and alimmen-sac are represented by dotted lines, 

 but a part of the yolk-sac is concealed beneath the cave-like diverticulum of 

 the albinnen-sac. In Fig. 21 the areas KDEF'K and KGHE are part of the 

 folded iuterallantoic septum, and the areas ADK and XZÖY (Fig. 20) are the 

 minor septa formed by the left and right allantoic artery respectively. The 

 sero-anmiotic connection is represented isolated in Fig. 50. 



