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C. H. CRABILL 
inoculate plates. In the resulting colonies sectoring was prominent. 
The plus sectors were about equal to the minus in number, somewhat 
less in width and were decidedly distinct as usual. 
In some of the photographs appended it is evident that the minus 
sectors of certain colonies are not quite sector-shaped in outline 
but narrow somewhat toward the margin (Figs. 7 and 11). As stated 
Fig. 15. Enlarged photograph of the IV colony shown in Fig. 12. The 
mycelium in the minus sector is almost entirely hyaline and fruitless. In the plus 
sector the color zone which was much broader a few days previous is very narrow 
and surrounds the outermost ends of the mycelium. Some of the color has diffused 
out into the agar. 
above, when pieces of agar containing mycelium of the two were used 
to inoculate simultaneously the minus sectors were larger than the 
plus sectors. These observations together with measurements of 
the rate of growth in colonies of like age indicate that unless the plus 
strain has a relatively large amount of inoculating material to start 
from, the minus strain will predominate in growth volume. This is 
