| | PAGE. |
| Part I. Introductory | [5] |
| Mendel's law of segregation | [5] |
| Linkage and chromosomes | [5] |
| Crossing-over | [7] |
| The Y chromosome and non-disjunction | [8] |
| Mutation in Drosophila ampelophila | [10] |
| Multiple allelomorphs | [11] |
| Sex-linked lethals and the sex ratio | [14] |
| Influence of the environment on the realization of two sex-linked characters | [16] |
| Sexual polymorphism | [17] |
| Fertility and sterility in the mutants | [18] |
| Balanced inviability | [19] |
| How the factors are located in the chromosomes | [20] |
| The sex-linked factors of Drosophila | [21] |
| Map of chromosome X | [22] |
| Nomenclature | [24] |
| Part II. New data | [25] |
| White | [25] |
| Rudimentary | [25] |
| Miniature | [26] |
| Vermilion | [27] |
| Yellow | [27] |
| Abnormal abdomen | [27] |
| Eosin | [28] |
| Bifid | [28] |
| Linkage of bifid with yellow, with white, and with vermilion | [29] |
| Linkage of cherry, bifid, and vermilion | [30] |
| Reduplicated legs | [31] |
| Lethal 1 | [31] |
| Lethal 1a | [32] |
| Spot | [33] |
| Sable | [34] |
| Linkage of yellow and sable | [35] |
| Linkage of cherry and sable | [37] |
| Linkage of eosin, vermilion, and sable | [37] |
| Linkage of miniature and sable | [40] |
| Linkage of vermilion, sable, and bar | [40] |
| Dot | [44] |
| Linkage of vermilion and dot | [44] |
| Bow | [46] |
| Bow by arc | [47] |
| Lemon body-color | [48] |
| Linkage of cherry, lemon, and vermilion | [48] |
| Lethal 2 | [49] |
| Cherry | [51] |
| A system of quadruple allelomorphs | [51] |
| Linkage of cherry and vermilion | [51] |
| Compounds of cherry | [52] |
| Fused | [53] |
| Linkage of eosin and fused | [54] |
| Linkage of vermilion, bar, and fused | [56] |
|
Forked | [58] |
| Linkage of vermilion and forked | [59] |
| Linkage of cherry and forked | [59] |
| Linkage of forked, bar, and fused | [60] |
| Linkage of sable, rudimentary, and forked | [61] |
| Linkage of rudimentary, forked, and bar | [62] |
| Shifted | [63] |
| Linkage of shifted and vermilion | [63] |
| Linkage of shifted, vermilion, and bar | [64] |
| Lethals sa and sb | [64] |
| Bar | [66] |
| Notch | [66] |
| Depressed | [67] |
| Linkage of depressed and bar | [67] |
| Linkage of cherry, depressed, and vermilion | [68] |
| Club | [69] |
| Genotypic club | [70] |
| Linkage of club and vermilion | [70] |
| Linkage of yellow, club, and vermilion | [70] |
| Linkage of cherry, club, and vermilion | [72] |
| Green | [73] |
| Chrome | [74] |
| Lethal 3 | [74] |
| Lethal 3a | [75] |
| Lethal 1b | [76] |
| Facet | [76] |
| Linkage of facet, vermilion, and sable | [77] |
| Linkage of eosin, facet, and vermilion | [78] |
| Lethal sc | [79] |
| Lethal sd | [79] |
| Furrowed | [80] |
| Additional data for yellow, white, vermilion, and miniature | [80] |
| New data contributed by A. H. Sturtevant and H. J. Muller | [82] |
| Summary of the previously determined cross-over values | [83] |
| Summary of all data upon linkage of gens in chromosome I. | [84] |
| Bibliography. | [86] |