516 
separates the right lobe (on its right side) from the left lobe, and 
corresponds to the notch produced by the left set, of allantoic vessels 
in Fig. 2. At its posterior end runs the left set of the allantoic vessels. 
The seam that separates the middle from the left lobe corresponds to 
the posterior constriction of Fig. 2, and is different from the other two: 
(1) in that it has interposed in it the sero-amniotic connection, (2) in 
that it passes over to the dorsal side. At its dorsal end are the remnant 
of the posterior tube of the amnion, and certain other structures which 
need not be entered into here. 
15. Just opposite the center of the tri-radiate seams, a small 
mass of the white which has disappeared very early from over the 
embryo, persists up to a very late date (Diag. VI). It seems to have 
=> = -— > 
_ --— 
laa ~ 
Man to's SS 
nm N 
= 
= 
-= 
h_ m 
IRB 
Cie 
en 
= 
== 
undergone some change in its chemical composition, for it is now 
much denser, slightly yellowish in color and sticky. To receive this 
mass, the membranes are often slightly indented, and into the mass a 
