INHERITANCE OF EYE-COLOUR IN GAMMARUS. 41 
The H. ¢ of Exp. 75 had two broods of 21—1n one case 13 Black and 
8 Red, in the other 13 Red and 8 Black. 
The number of young in a brood varies with the individual, but the 
numbers in the broods of a single pair do not vary much asa rule; to take 
an example, Exp. 99 had seven broods as follows: 11, 15, 13, 10, 11, 15, 11. 
Exp. 35 is an interesting one, showing the varying proportions of Black 
and Red with different mates. This female was mated with four males 
with the following results : with male a, one brood of 13 young, 3 Black, 
10 Red ; with male b, one brood of 10, 8 Black, 2 Red ; with male c, two 
broods of 28 and 27, with 12 Black and 16 Red, and 11 Black and 16 Red 
respectively ; and with male d, two broods of 11 and 23, with 6 Black 
and 5 Red, and 14 Black and 9 Red respectively. 
Many of the F, animals had died by the time these experiments were 
finished, only a few remained to be mated together. Two matings of 
P. x P. were made, the other P. animals being paired with H. mates. 
IEaSCE. Exp. 83a 5 broods 133 Black-eyed young. ¢ died. 
‘ ie ae 61 p @died! 
Pec H. ,» 84 Ibrood Eggs thrown off. S died. 
E<H. cB LODE a 5, 6 Black-eyed young. ¢ eaten. 
Boi, Lie) 2breeds. -St48 Zf 2 ¢$ died. 
ET: ES DY Ar ordod 5 A fe ¢ died. 
eos Es sing (5 Ln) el Miata 43 ) “ 3 died. 
13 i Aa a ~ Shion” a broods "So i + ¢ died. 
eee ch eee lOobe 473 * 113 is 4s ¢ eaten. 
da Up od , lo? — a ? died. 
ee cr Boel toe - it brood 5 A a 3 died. 
1 ADS eal Set i i an 3 died. 
Total . . In21 broods 497 Black-eyed young. 
The matings of H. x H. are as follows :— 
H.xH. Exp. 86 2 broods 60 young = 46 Black 14 Red. 9 eaten. 
Fee cei Oo Peprood 2a = LOR Se Gree 
and another brood 
($ unhealthy) Le ere $ died. 
ec xp. 06a VT brood 52° = == "48 4, S died. 
- ,, 106b — = — — © died. 
Heche 109" “broods 6205 v= 437 °F "19-5, gd died: 
Hea ee -hleg k'brood: 38° 9 = 300 55 8" gy hi died: 
Ee Chee i eprdods 400 8 == 29" Ils, Both died. 
Ee eta 1G) brood wb ea 2, oS died. 
Total . In12 broods 286 young =220 Black 66 Red. 
