AND ruE Foetal membranes, in the chu'k. 



855 



(lie figlit of the coiiijecti<Jii (Figs. S, 1), jiikI 11). Whether the sero- 

 aiiiniotic connection, towards which th(; alJantois s[)re!ids itself, is able 

 to persist by the presence of the allantoic vein, or the niargiji of the 

 allantois is specially indented by that vein on account of tlie presence of 

 the sero-aniniotic <'onnectioii, is a question which can not be answered 

 at present. 



The overlapping of the allantoic ]ol)es which began at the apex <,)f 

 the indentation and spread gradually [»eripherally (Fig. 10) progresses 

 without any hindrance, until it reaches the sero-anuiiotic connec- 

 tion. As this otfers an impassable 



Diag. 7. 



A Longitudinal Section. 



Diag. 8. 



^eia 



Allantoic cavity. 



A Surface \'ie\v. 



Egg in the 'Jth Dii,y of luculjatiou. 



obstacle, the allantoic lobes with 

 their serous envelopes rise alcove 

 the level of the sero-anmiotic con- 

 nection, and pass beyond it, pro- 

 je(.'ting like the eaves of a roof. 

 Diag. 7, which is a longitudinal 

 secticjn thrijugh the plane oi' the 

 overlapping, shows how tlie allan- 

 tois has risen above tlie sero- 

 aniniotic connection and passed 

 lje}ond. There is thus jtroduced, 

 above the yolk sac and below the 

 allantois, a sort of cave, at whose 

 blind end is the sero-anmiotic 

 connection. Diau-. ,S yives a sur- 

 face view of these ])oints. The 

 part marked with lines slanting 

 to the left shows the area of over- 

 lapping, wiiile tiie part niai-ked 

 with lines slantinu' to the rii-ht 



