28 E. W. SEXTON AND M. B. WING. 
numbering 422 young (these are the F, generation), average 7 per brood, 
a smaller average than in the preceding generation. 
In the F’, generation the same system was followed as in the F,, the 
ovigerous females being removed from the brood-bow] till they had ex- 
truded their young, and then returned to it. But in one or two cases 
where only males or only females were left of a brood, mates from a 
different brood, but of the same family and the same generation, were 
added. These records were kept separately. The females of the first 
category laid 26 broods between September, 1914, and October, 1915, 
and hatched 207 young. One pair mated twice with no results, and two 
other pairs also mated with no results. In the second case, where male 
and female came from different broods, only two broods, of 7 and 8 
young respectively, were hatched, the male in each case dying soon after, 
but these broods appear stronger than the others. 
Several of this F, generation are still breeding (Nov. 3, 1915), 
but the numbers already obtained are sufficient for proof and 
record. 
Of the F, generation 105 have survived (Nov. 19, 1915), many of them 
not yet mature. In several broods all the individuals have very pale eyes, 
with hardly any of the red pigment showing. The results for this genera- 
tion are unsatisfactory, only a few young being hatched. Ten pairs have 
mated so far, as follows :— 
From the first category (individuals of the same brood paired in their 
brood-bowl) 2 pairs mated, no eggs laid; 1 pair mated, eggs thrown off ; 
3 pairs with 18 young in 4 broods. 
From the second category, which appears to yield a stronger stock (the 
two F, broods of the two F, pairs in which male and female came from 
different parents), 4 survive of the first brood of 7, not yet mature; the 
second brood of 8 matured, and 6 matings have taken place: 4 young (all 
dead now); eggs thrown off; no eggs; 9 young (all dead); 7 young 
(1 left) ; and 5 young (3 left, mature females). 
The total number for the F,4 generation thus far is only 31. Some 
individuals of one brood, the 9 young referred to above, came to maturity, 
and 2 broods of #’, were hatched, numbering 12 young. Of these 9 sur- 
vived, and are now nearly ready to breed. 
II. THE: DOMINANTS. 
The Dominants are divided into Pure Black and Hybrid Black, which 
will be dealt with under separate divisions. 
Aecording to the Mendelian laws of inheritance of characters, the 
