304 



Prorrrdiiifjs of IiKliana Academy of Science. 



2. Spineless 9 l>y curved o'. 



Tile reeiproeal cross ia which the spineless 9 is paired to the curved cf 

 is given in tabl ' IV. All the Fi were like the wild type. 



Table IV. F2 generation from spineless 9 by curved cf . 



Tables III and IV give evidence of free Mendelian assortment of curved 

 and spineless since the classes approximate a ratio of 9:3:3:1. We con- 

 clude that the gene for curved is borne by a chromosome other than III. 

 3. Deficiency of the douMe recessive curved spineless in crowded conditions. 



These combinations have been made many times with the same result 

 except that when the cultures are crowded there is a marked suppression of 

 the double recessive. Table V gives an F, count from crowded conditions. 

 It is to be noted that only approximately half the number of double reces- 

 sives appear under unfavorable conditions. 



