142 CHAPTER 11 



FIGURE 18-3. Salircirv gland chromosomes of a female larva of D. melanogaster. 

 {Courtesy of B. P. Kaitfmann; by permission of The American Genetic Association, 

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



FIGURE 18 4. A band (at top) cmd 

 interband {below) region of a stretched 

 Drosophila salivary gland chromosome. 

 Photographed with the electron micro- 

 scope at a magnification of approxi- 

 mately I2,200X. Present enlargement 

 is about ]3,000X. {By permission of 

 The American Genetic Association, 

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

 1952.) 



FIGURE 18-5. The pair of fourth chro- oUALL |-^ 3 /-< >| 



mosomes, drawn to the same scale, as 

 seen in salivary gland nuclei {each homo- 

 log is highly polytene) and at mitotic 

 metaphase {arrow). {By permission of 

 The American Genetic Association, 



C. B. Bridges, '^Salivary Chromosome ^ \ i 



Maps,'' Journal of Heredity, vol. 26, Jl^-r^-" ^'' 



p. 62, 1935.) 





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