174 A - RICHARDS. 



EXPLANATION OF PLATE VI. 



FIGS. 45-49. Stages in the development of the yolk body in the vitellarium 

 cells. King, Conklin's stain. 



FIG. 50. The appearance of a much decolorized yolk mass.^ b is the same yolk 

 mass shown in a at a lower level; probably the central bodies here are remnants 

 of the yolk nucleus. King, iron hcematoxylin. 



FIG. 51. Cells early in the development of the female genital "ducts. Cyto- 

 plasmic boundaries are not well fixed in this preparation. The nuclei show no evi- 

 dences of division either direct or indirect. Arrow points in the direction of the 

 axis of the duct. King, iron haematoxylin. 



FIG. 52. A cross section from a somewhat later stage in oviduct formation. A 

 case of mitosis is shown here. Formol-sublimate, iron hsematoxylin. 



FIG. 53. First maturation division of an oocyte. King, iron hsematoxlyin. 



FIG. 54. Second maturation division. Zenker, iron haematoxylin. 



