Figure 229.— Blood from heart, of chick embryo. Incubation age, 13 days 16 hours. 1,370X. 



1 



2-4 



5-13 



14-16 



Mature primary erythrocyte. 



Mid-polychromatic erythrocytes, all of which show 



artifacts of cytosomal fracturing. 



Late polychromatic erythrocytes; some show 



artifacts of cytosomal fracturing. Two cells, 7 and 



13, are nearly mature. 



Mature erythrocytes. 



17 Microcyte. 



18 Ery thro blast or thromboblast. 



19 Small embryonic thrombocytes that have clumped 

 and disintegrated the cytoplasm. 



20 Basophil mesomyelocyte. The presence of any granu- 

 locyte in the circulating blood of the embryo is rare. 



106 



