EARLY DEVELOPMENT OF THE PIGEON'S EGG. 



245 



clei and such relations between the segmented and unsegmented 

 part as to suggest contribution of cells from the periblast. Of 

 course, such segregation of cytoplasm and granules around nu- 

 clei as is indicated at 2 and 3 may not be permanent. The nu- 

 cleus for the cell at 3 is in the next section. Amitotic division 

 is suggested by some of the nuclei. Compare the position of 



2 5 





3 



/ 1 





•/•••"• *.V' 



L 





Fig. 12. Marginal part of a horizontal section through a pigeon's egg about 

 twenty-five hours after fertilization, 8:50 P. M. i. Periblast nuclei. 2 and 3. Cells 

 being organized out of the syncytium. The nucleus for 3 is in the next section. 

 4. A cell contributed from the periblast. 5. Vacuole. 



nuclei in a syncytial zone outside the segmented blastodisc with 

 the condition shown in Wilson's " Embryology of the Sea Bass" 

 (8), Figs. 23 and 24. 



The following outline drawings, Figs. 13, 14, and 15, need 



Fig. 13. Margin of a transverse section of a pigeon's egg, about 26 hours after 

 fertilization. Notice cells being added to the segmented part from the periblast. The 

 periblast nuclei were not all in this section, but were found in four successive sections. 

 Two nuclear nests are shown. 



little explanation. They are of transverse sections of eggs about 

 26, 28 and 32 hours respectively after fertilization. They sug- 



