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LINKAGE 



spring recorded is small. In such cases the data are 

 usually fitted to the nearest ^^Mendelian" ratio even 



I 



3 



Fig. 28. — Photograph of the Pi (1 and 2) and Fi (3 and 4) birds in such 



a cross as that of Fig. 26. 



though discrepancies are apparent. Even in species 

 where a number of different characters have been 

 studied these are often recorded in separate tables. 



