PROCEEDINGS OF SCIENTIFIC SOCIETIES. 499 
backwards; the mouth is situated between the anterior pair. The whole 
embryo covers but about a third of that portion of the yolk in sight. At 
this time the inner egg membrane (blastoderm-skin?) was first detected. 
he outer membrane, or chorion, is structureless; when ruptured the 
torn edges show that it is composed of five or six layers of a structure- 
less membrane, varying in thickness. The inner egg membrane is free 
from the chorion, though it is tm contact with it. Seen in profile it con- 
sists of minute cells which project out, so that the surface appears to be 
finely granulated. But on a vertical view it is composed of irregularly 
E 
waved, or have from three to five long slender projections, with the ends 
sometimes knobbed, directed inwards. These cells are either packed 
e ce: 
asubsequent stage (Fig. 96) the oval body of the embryo has in- 
creased in size. The segments of the cephalothorax are indicated, aud 
Fig. 98. 
Fig. 97. 
cephalothorax, the sides of which are not spread out as Ina later stage. 
At this stage the egg-shell has burst, and the “amnion” increased in size 
several times exceeding its original bulk, and has admitted a correspond- 
