NEW DATA. 



83 



SUMMARY OF THE PREVIOUSLY DETERMINED CROSS-OVER VALUES. 



The data of the earHer papers, namely, Dexter, 1912; Morgan, iQior, 

 1911^, 1911/, 1912/, 1912^; Morgan and Bridges, 1913; Morgan and 

 Cattell, 1912 and 1913; Safir, 1913; Sturtevant, 1913 and 1915; and 

 Tice, 1914, have been summarized in a recent paper by Sturtevant 

 (Sturtevant, 191 5) and are given here in table 64. Our summary com- 

 bines three summaries of Sturtevant, viz, that of single crossing-over 

 and two of double crossing-over. 



Table 64. — Previously ptiblished data summarized from Sturtevant, IQIS- 



