252 N. M. Stevens, Further Studies on the Ovogenesis of Sagitta. 
Fig. 14a. End view of a tetrad. Zeiss’ obj. 1.5, oc. 6. 
Fig. 14b. End view of a dyad. ZEISS’ obj. 1.5, oc. 6. 
Fig. 15. Two polar spindles from eggs of the same individual as 
Fig. 11, showing dyads. Zeiss’ obj. 1.5, oc. 6. 
Fig. 16. Two polar spindles, end to end and radial, showing dyads. 
a 2d polar spindle; b division corresponding to that of the 1st polar body. 
Zeiss’ obj. 1.5, oc. 6. 
Fig. 17. Two polar spindles with inner poles united; a part of the 
chromosomes in another section. The chromosomes here are univalent. 
ZIETSSsobj. 1.5, 0c.26. 
Figs. 18 and 19. Young oocytes containing the somatic number of 
chromosomes (18). ZEISS’ obj. 1.5, oc. 6. 
Fig. 20. Young oocyte showing paired chromosomes, ZEISS’ obj. 1.5, 
oc. 6. 
Figs. 21-23. Young oocytes showing longitudinally paired chromo- 
somes. ZEISS’ obj. 1.5, oc. 6. 
Figs. 24a and b. Spermatocytes showing preliminary longitudinal split. 
ZEIss’ 2 mm, oc. 8. 
Fig. 25. Section of nucleus of nearly ripe oocyte, showing chromo- 
somes much reduced in size, and granules passing out along strands of 
karyoplasm. ZEISS’ obj. C, oc. 6. 
