462 
J. BRONTE GATENBY. 
Fig. 24. — Spermatocyte of Orgyia at end of growth-period to show 
mitochondria and other cell inclusions (Flemming with reduced 
acetic acid). 
Fig. 25. — Three oocytes of S. populi in contraction figure stage, 
showing micromitosome (M.), spindle bridge ( S.B . ), centrosome ( C .), 
and mitochondria ( M.D. ). Drawn to same scale as the spermatocyte 
in PI. 23, fig. 4 (Champy). 
Fig. 26. — Oogonium before contraction stage showing spindle bridge 
in transverse section, surrounded by mitochondrial cloud. Micromi- 
tosome (M.) near the upper end of the cell (Champy). 
Fig. 27. — First spermatocyte division of Orgyia antiqua showing 
spindle granules ( S.G .) and other cell structures (Flemming with 
reduced acetic acid). 
Fig. 28. — Oogonium of S. populi with spindle bridge in longitudi- 
nal section. Shows also, micromitosome (M.), mitochondria ( M.D . ), 
and two centrosomes (Champy). 
Fig. 29. — Oocyte of S. populi showing appearance of cell inclusions 
at later stage. 
PLATE 25. 
[All figures on left side of Plate 25 are drawn at table level with 
camera lucida, with a T Vtli Koritska semi-apochromatic oil immersion 
lens and compensating eye-piece 18, and in reproduction reduced by 
one half. In all these figures the mitochondria have been blackened in 
order to show them more clearly. On the right side of the Plate, 
figs. 43, 45, 46, 48, 49, 52, 53, 54, and 55, are at same magnification. 
Figs. 44, 47, 50, and 51 are twice the magnification.] 
Fig. 30. — Binucleate spermatocyte near end of growth stage. It 
contains two micromitosomata, and has an accessory centrosome near 
the top of the plate. The acroblasts are also shown. 
Fig. 31. — Spermatocyte to show appearance of mitochondria caused 
probably by fixative. The central bodies have run together to form 
rods. 
Fig. 32. — Spermatocyte in first maturation division showing mito- 
chondria and acroblasts. 
Fig. 33. — Section through X. — X. in previous figure. 
Fig. 34. — Second maturation division showing mitochondria and 
acroblasts. 
Fig. 35. — Young spermatid, showing incipient formation of macro- 
mitosome. Acroblasts becoming spherical. 
Figs. 36, 37, 38, and 39, later stages in formation of macromitosome, 
and acroblasts are shown. 
