I? 2 A. RICHARDS. 



EXPLANATION OF PLATE V. 



FIGS. 33-35. First oocytes, the ovarian eggs. Yolk globules shown in black 

 in Fig. 35 and indicated by dotted circles in the other figures; chromatin in the 

 characteristic arrangement. Two peculiar black bodies in Figs. 34 and 35 may 

 perhaps be centrosomes or spheres. Fig. 33, King, iron haematoxylin; 34, Zenker, 

 Ehrlich-Biondi; 35, King, iron haematoxylin. 



FIGS. 36-50. Development of the vitellarium. Character of the early devel- 

 opment is shown in Figs. 4 and 6 from the primary anlage. 



FIG. 36. Corresponds to Fig. n in time of development. Zenker, Ehrlich- 

 Biondi. 



FIG. 37. Same stage as Fig. 12. King, iron haematoxylin. 



FIG. 38. Growing vitellarium cell from some section as Fig. 15. King, iron 

 haematoxylin. 



FIG. 39. From the medullary portion of the anlage, the shell gland from the 

 same section as Fig. 37. Cytoplasm drawn out into fibers. 



FIG. 40. Shell gland region; same slide as 41 and 42. 



FIGS. 41 and 42. Vitellarium cells; both cells simulate mitosis due to the 

 heavy linin strands across their centers. Fig. 42 was at first taken for a case of 

 "endogenous division." King, iron hasmatoxylin. 



FIG. 43. From growing vitellarium, about the same stage as Fig. 20, a charac- 

 teristic mitosis. King, iron haematoxylin. 



FIG. 44. Just before the formation of the yolk body. The dense cytoplasmic 

 mass is probably a yolk nucleus. King, iron haematoxylin and Bismarck Brown. 



