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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt:...cross, proved to be different. The cross was made up using eosin against yellow notcli2. A summary of the results is given in table 6. Inspection of the Table 6 In this summary, the 321 females, not separately classified, occurred in cultures when a wild-type male was used. Only the males of such cultures could be used for crossover determination. crossovers obtained shows the complete absence of representatives of a double-crossover class. The missing class would be yellow or notch eosin. The sequence is yellow notch eosin, which does not agree with the sequence in melanogaster, namely, yellow eosin notch. The result was a surprise, and while the above data seemed convincing enough, the cross was repeated in another way, using yellow eosin in one chromosome against notch2 in the other. The results obtained in the second cross confirmed those obtained in the first. Four cultures are summarized in table 7. Here the class yellow or notch eosin, which was missing in the pre Table 7 yellow eosin Nature of the cross: 9 X yellow eosin cf. A otch vious cross, is now present, while the triple-mutant and the wild-type class are absent. Both crosses indicate the same sequence, namely, yellow notch2 white (or eosin). A consideration of the difference in sequence as compared with that of the similarly named mutants in D. melanogaster will be found in a later section of this paper. Having determined the sequence, the map distances may be calculated, using all the available data for these two regions, which is given in the regional summary. A yellow notch distance of 5 units is obtained, and a notch white (or eosin) distance of 1 unit. These three loci have their position in the linkage group to the left of vermilion. The yellow vermilion distance is about 14 units, with...