i! Id The Oo^^ciu'sis of tlic 'roi'ioiso 



usual, numerous yolk-nuclei distributed throughout the cytoplasm; an irreg- 

 ular cytocenter; first yolk-bodies at the subcuticular zone of cytoplasm. 



PLATE VI. 



Pio. 78. Section of an egg showing germinal vesicle; numerous yolk- 

 nuclei in cytoca^l; a plasma channel; a reticular cytocenter; the first true 

 yolk-bodies. 



Fig. 79. Section of an egg through the germinal vesicle, nearly at right 

 angles to the egg axis, showing the germinal vesicle and the relation to it 

 of the large yolk-nucleus forming an incomplete ring around the germinal 

 vesicle; numerous smaller yolk-nu(dei scattered throughout the cytoi)lasm; 

 also the first yolk-bodies at the subcuticular layer of cytoplasm. 



Fic). 80. Section of an egg, showing germinal vesicle, peripheral nucleoli, 

 and many small yolk-nuclei surrounding it; a conspicuous aster-like cyto- 

 center, and numerous large yolk-nuclei both regular in outline and also very 

 irregular and staining very deeply; yolk-bodies at the periphery. 



Fici. 81. Section of an egg, showing a germinal vesicle with peripheral 

 nucleoli and many small yolk-nuclei surrounding it; a plasma channel ap- 

 parently connected with the germinal vesicle, as seen from reconstructed 

 serial sections; numerous yolk-nuclei occupy the cytocoel and seem to sur- 

 round the plasma channel as if isstiing from it; a somewhat reticulated 

 cytocenter having no similarity to the yolk-nuclei. 



Fig. 82. Section showing the germinal vesicle with bead-like chromosomes, 

 peripheral nucleoli; yolk-nuclei, and their relation to the germinal vesicle 

 and to the cytocoel; a spherical, definitely bounded cytocenter with granular 

 center and reticulated outer portion. 



Fig. 83. Section showing germinal vesicle with nucleoli; and a large 

 spherical yolk-nu(^leus connected with the germinal vesicle; numerous smaller 

 ones in the cytoc'cKl; a spherical cytocenter. 



PLATE VIL 



Fid. 84. Section of an e.gg, showing germinal vesicle; a fibrous cytocenter, 

 surrounded by a zone of cytoreticulum; the order of yolk formation in zones — 

 the outer yolk zone just under the subcuticular zone, and the second in the 

 cytocoel. 



Fid. 85. Section of an egg considerably larger than the previous, showing 

 the relative inc^rease of the two yolk zones and the relation of these to the 

 germinal vesicle and to the cytocenter, c.c. The cytocenter is surrounded by 

 a /one of |)rotoplasm, tlio inner cytoca^l, L vy. c: this again surrounded by 

 the inner yolk layer, i. y. I., this surrounded by the outer cytocoel o. cy. c, 

 followed by the outer yolk layer, o. y. I; outside of this the subcuticular layer, 

 vc. I. Surrounding the sub('uti('ular layer is th^ striated membrane, st. m., 

 outside of whicdi is the homogeneous membrane, h. vi., the two constituting 

 the egg membrane or chorion. The follicle, //., forms a single layer of cell 

 surrounding the egg. 



Fig. 86. Section of an egg more advanced than the preceding as is evident 

 from the greater development of the yolk. The yolk-bodies have encroached 

 on the (!ytocenter which is reduced to a crescentic mass of granular sub- 

 stance staining differently from the rest of the cytoplasm. The section shows 



