ERYTHROBLASTS IN THE PIG EMBRYO 



193 



DESCRIPTION OF FIGURES 



Figures 1 to 12 a are from fixed blood vessels, figures 13 to 45 from fresh unfixed 

 material and cultures. All the figures are camera lucida drawings. Figures 1 to 

 12 a were made with a No. 4 Zeiss compensating ocular and an oil immersion 2 mm. 

 apochromatic objective, and figures 13 to 45 with a Leitz ocular No. 4, and No. 

 7 objective, the drawing-board being at the level of the table. The numerals at 

 the right or left in figures 13 to 20 and 34 to 36, indicate respectively the time at 

 which the observations were made. 



ABBREVIATIONS 



e, erythroblasts approximating the 

 height of fheir differentiation prior 

 to the formation of plastids 



em, erythroblasts undergoing mitotic 

 division 



eu, undifferentiated erythroblasts 



ep, partly differentiated erythroblasts 



n, erythrocytic nuclei 



nf, erythrocytic nuclei with no evident 



surrounding cytoplasm 

 p, plastid 

 pi, large plastid 

 p)n, medium-sized plastids 

 ps, small plastids 

 ((', wall of blood vessel 



