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figure 1 1 -4. Salivary gland chromosomes of a female larva of D. melano- 

 gaster. (Courtesy of B. P. Kaufmann; by permission of The American Genetic 

 Association. Journal of Heredity, Frontispiece, vol. 30, No. 5, Max, 1939.) 



I K.i RE 1 1-5. A hand (at lop) and 

 interhand (below) region of a 

 stretched Drosophila salivary gland 

 chromosome. Photographed with 

 the electron microscope at a magni- 

 fication of approximately J2.200X- 

 Present enlargement is about 

 13.000X. (By permission of The 

 American Genetic Association. Jour- 

 nal of Heredity, vol. 43, p. 231. 

 1952.) 



figure 1 1-6. The pair of fourth 

 chromosomes as seen in salivary 

 gland nuclei ( each homolog is highly 

 polynemic) and at mitotic metaphase 



(arrow), drawn to the same scale. 

 I By permission of The American 

 Genetic Association. C. B. Bridges, 

 "Salivary Chromosome Maps," Jour- 

 nal of Heredity, vol. 26, p. 62, 

 1935.) 



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