FiGUKES 288-307. — Late developmental stages of the embryo thrombocyte 



297 



2,470X. 



Figures 288-291 : Large functional embryo Diroinbocyles. 

 Drawn, from same slide as figures 280-286. 



288 Large embryo thrombocyte showing blebs of early 

 disintegration. 



289 Large embryo thrombocyte showing partial loss of 

 basophilic cytoplasm. 



290 Vacuolization of cytoplasm with loss of staining 

 affinity. A stage in the differentiation process. 



291 Discharge of chromatin granules into the cytoplasm. 

 Found only in well-preserved early embryo material. 



Figures 292-295: Medium and small embryo thrombocytes. 



292 Medium embryo thrombocyte. Vacuolization and 

 some discharge of nuclear chromatin. 



293 Medium embryo thrombocyte. Several chromatin 

 bodies in cytoplasm. Pink color due to early dis- 

 integration of the cell. Embryo incubated 5 days 21 

 hours. 



294 Small embryo thrombocyte. Same type shown in 

 figure 229, 19. Embryo incubated 7 days 23 hours. 



295 Medium embryo thrombocyte. Cytcsome partly 

 disintegrated. Embryo incubated 8 days 21 hours. 



Figures 296-303: Stages in development and breakdown of 

 late embryo thrombocytes. Embryo incubated 9 days 15 

 hours. 



296 Medium embryo thrombocyte. Slight autolysis at 

 the cell margin. Cytosome contains more than the 

 usual number of specific granules. 



Medium embryo thrombocyte. Acidophilia and 

 folding of cell margin are first steps in cell disintegra- 

 tion. Three specific granules present. 



298 Medium embryo thrombocyte. Less differentiated 

 than preceding cell. One specific granule. 



299 Medium embryo thrombocyte. Folding of cell 

 margin well started. Two specific granules. 



300 Small embryo thrombocyte. Much of the cyto- 

 plasm lost. One specific granule. 



301 Small embryo thrombocyte. Much of the cyto- 

 plasm lost. No specific granule visible. 



302 Mature embryo thrombocyte. A specific granule at 

 each pole. 



303 A binuclear mature embryo thrombocyte. Nu- 

 merous specific granules. 



Figures 304-307: Developmental stages of thrombocyte 

 generations coming late in embryonic life. 



304 Medium embryo thrombocyte. Early stage of 

 development. No specific granules. Embryo incu- 

 bated 13 days 15 hours. 



305 Medium embryo thrombocyte. Later stage in dif- 

 ferentiation than preceding cell. Same slide as 

 figure 304. 



306 Small embryo thrombocyte. Nucleus and cyto- 

 plasm undergoing degeneration. One specific 

 granule. 



307 Definitive thrombocyte, nearly mature. One spe- 

 cific granule. Embryo incubated 17 days 14 hours. 



136 



