GROWTH AND TRANSFORMATION 151 



stored in it. So great is this that the egg-protoplasm 

 necessarily forms centrally a diffuse network, with a con- 

 densed circumferential layer within the envelope or shell 

 of the egg ; in the central network the yolk spheres, 

 relatively large transparent bodies, are found, as well as a 



Pig. 39.— a, B, C, Embryonic Development of a Tortricid Moth 

 {Eudemis naevana), as shown in transverse sections of the egg-shell with 

 embryo at successive stages. X 50. g, germ band ; a, amnion ; s, serosa ; 

 y yolk • V, vitellophags (yolk-absorbing cells) ; ec, ectoderm ; en, inner- 

 cell mass (endoblast or ventral plate). After L. H. Huie {Proc. R. Soc. 

 Edinh. xxxviii, 1918). 



number of minute corpuscles. The egg thus contains a 

 diffused mass of living protoplasm capable of division and 

 growth, and a quantity of food-material for nourishing the 

 developing embryo. Such a relatively large, heavily yolked 

 egg is common in the great comprehensive group of animals 



