PLATE VII 



Paired Chromosomes in the Salivary Gland Nuclei of Diptera 



Fig. I. — Living nucleus of Chirojiomus Thitmmi, •w = 4, in liquid 

 paraffin. The small fourth chromosome has a nucleolus attached 

 and lies in the middle. x 635. (Bauer, 1935.) 



Figs. 2 and 3. — Drosophila pseudo-obscitva, aceto-carmine smear 

 preparations (c/. Text-Figs.), 



Fig. 2. Complete nucleus of female showing inversion-pairing 

 in third chromosome. Fig. 3. One pair of chromosomes in a 

 heterozygote showing inversion and deletion pairing and relic 

 coiling. (Koller, 1935, 1936.) 



Fig. 4. — Part of chromosome of Chiroiiomns sp. drawn out to show 

 threads connecting chromomeres. (Koller, 1935.) 



