OF MUTANT CHARACTERS. 301 



at about 80 per cent, and a cross-over value of 35.9 corrected to 37.6 

 according to the probable coincidence of 30. The net coincidence in 

 the case of purple speck is about 50, so that the value of 45.7 may be 

 corrected to 53.6, with a locus of 59.8 The weighting corresponding 

 to this distance and coincidence is about 70 per cent, or there is the 

 equivalent of 8,390 flies. The mean position for the locus of speck is 

 at about 58.6 units to the right of black. 



The establishment of the foregoing loci complete what may be called 

 the " triangulation" for the map of the second chromosome. The 

 remaining loci are filled in secondarily with relation to one or more of 

 these bases, or in the case of a few, the relation to still other loci must 

 be considered. .Thus the position of morula is dependent primarily 

 on the position of arc, which must first be located. The mean position 

 of arc is found by means of the arc speck value of 5.9 based on 2,625 

 flies, the purple arc value corrected to 44.2 (C = 40) and weighted at 

 1,838. the black arc value corrected to 52.1 (C = 70) and weighted at 

 3,038, to be 51.9 units to the right of black or 6.7 from speck. 



The position of morula at black + 59.8 is based entirely on the arc 

 morula value of 7.9 found from 6,794 flies. 



The remaining loci will be treated very briefly in the order of their 

 appearance. 



The locus of olive is not exactly known, nor is it important. The 

 probability is that it lies to the right of speck and not more than a unit 

 distant, or at 106.1 referred to star. 



The locus of truncate is best found from the star truncate value of 

 27.1 corrected to 28.0 (C = 25), which give a position 28 units to the 

 right of star. 



The locus of balloon is 0.4 unit to the right of speck (S'+ 105.5), 

 based on 462 flies. 



The locus of the lethal hypothecated in the chromosome homologous 

 to that carrying truncate (lethal T') is probably within 15 units of the 

 truncate locus as judged from the proportion of wild-type and truncate 

 flies in the highly selected stocks. 



The locus of blistered is approximately 2 units to the left of speck 

 (or at & + 103) as deducted from the qlistered speck cross-over value 

 and certain later indications. 



The locus of jaunty is very close to that of black, probably 0.2 unit 

 to the right (S'+46.7), on the basis of one questionable cross-over in 

 Muller's progeny tests. 



Strap, antlered, and nick are probably allelomorphs of vestigial with 

 the same locus (S'-}-65.0) If they are not allelomorphs, then their 

 loci are so close to that of vestigial that the interval is negligible. 



The locus of gap is suspected of being in the neighborhood of curved. 



The locus of comma is perhaps =*= 15 units from that of squat 

 (Sq' = S+35.5), as judged roughly from the distribution of squat and 

 comma. 



