Contents. 



Page 



VI. Linkage Group V 46 



Description, origin, and com- 

 parison of characters in 



Group V 46 



Fused 46 



Interrupted 46 



Branched 47 



Approximated 47 



Ruffled 47 



Linkage data 48 



Detection of hnkage in Group 



V 48 



Branched and fused 48 



Branched and approximated 48 



Fused and interrupted 48 



Interrupted and approxi- 

 mated 48 



Branched and ruffled 48 



Cross-over values 48 



Fused and interrupted 48 



Fused and branched 49 



Fused and approximated ... 49 

 Interrupted and branched . 49 

 Interrupted and approxi- 

 mated 49 



Branched and ruffled 50 



Discussion 50 



V'll. Linkage Gnoup VI 51 



Bent 51 



Linkage tests with bent 52 



Net 52 



VIII. Additional Characters 54 



Extra 54 



Spine 54 



Capsule 54 



Minus 55 



IX. Comparison of mutant characters 

 in D. virilis with those in other 



species of Drosophila 56 



Page 



IX. Comparison of mutant characters 

 — Continued. 



Comparison of sex-linked char- 

 acters 57 



Forked and singed series 57 



In D. melanogaster 59 



In D. mrilis 60 



In D. willistoni 60 



In D. obscura 60 



In D. simulans 60 



In D. funebris 60 



Relationships 61 



Comparison with sex-linked 



characters in D. melanogaster 63 

 Comparison with sex-linked 



characters in D. simulans. . . 64 

 Comparison with sex-linked 



characters in D. willistoni. . 64 

 Comparison with sex-linked 



characters in D. obscura. ... 65 

 Comparison with sex-linked 

 characters in D. funebris. ... 66 

 Comparison of autosomal char- 

 acters 66 



X. The case of vermilion, and the possi- 

 bility of a rearrangement of genes 69 

 XI. Comparison of X-chromosome 



maps 71 



XII. Coincidence 75 



XIII. Chromosomes and linkage groups 



compared 77 



XIV. Tabulation of linkage experiments 79 



Group 1 79 



Group II 90 



Group III 90 



Group IV 90 



Group V 91 



XV. Literature cited 93 



