292 CGEAVPOLE: 
EXPLANATION OF PLATE XXI. 
Cleavage. 
Fic. 15. External view of unsegmented eggs, showing grouping. Obj. 4, oc. 2. 
Fics. 16-24 are surface views of cleavage stages, showing the 2, 4, 8, 16, 32, 
and coarse morula stages until total cleavage ceases. Drawn from unstained 
eggs. Obj. 16, oc. 6. 
Fic. 25. Protoplasmic mass at the surface of egg. /fr., female pronucleus 
returning to centre; 7.0., polar bodies. Borax carmine. Obj. 7, oc. 6. 
Fic. 26. Showing division of first polar body. Letters as in Fig. 25. Borax 
carmine. Obj. 74, oc. 6. 
Fic. 27. Part of protoplasm from the centre of the unsegmented egg. /r., 
female pronucleus; .fr., male pronucleus. Borax carmine. Obj. 7s, oc. 6. 
Fic. 28. First cleavage spindle. Iron haematoxylin and Orange G. Obj. 
qs; OC. 2. 
FIG. 29. Reconstruction of nucleus after division into the 2-cell stage. 
Letters as before. Iron haematoxylin and Orange G. Obj. 4, oc. 4. 
