362 



Eye-Colour in Gammarus 



not know if being homozygous or heterozygous for colour would cause 

 a difference in the results, we had first of all to test the animals with 

 Pure Red mates before mating Albino with Albino. 

 The experiments therefore fall into two divisions :— ^ 



1. Albinos mated with Reds ; and 



2. Tested Albinos mated with tested Albinos. 



1. Albinos mated with Reds. 



The Albinos were taken from different broods of the C. 17 6 family ; 

 the Reds were drawn from one stock as far as possible, a mixed stock 

 (Pure Black x Pure Red) with no admixture of Albino and with very 

 few spots, the same stock as that from which the animals for the Un- 

 spotted strain experiments were taken. 



A great many were tested, but only the details of the larger families 

 are given. The Red mates were all unspotted. 



The following are the results of matings between the Unspotted 

 Albinos and Pure Reds : — 



1. Male carrying Bed 67 unspotted offspring 10 spotted 



2. Female „ , Black and Bed 98 ,, ,, 5 ,, 



3. Female „ * „ „ 33 „ .i 10 „ 

 5. Female „ Black 27 „ ,, 8 „ 

 9. Male „ Black and Bed 24 „ „ 3 „ 



10. Female ,, Bed 32 „ „ 6 „ 



11. Male „ „ 31 „ „ 2 „ 



12. Male „ „ 51 ,, „ 2 „ 



13. Male „ „ 56 „ „ 8 „ 



14. Male „ „ 66 „ ,, 3 „ 



64. Female „ Black and Bed 50 ,, ,, 11 „ 



65. Female ,, ,, ,, 54 ,, ,, 5 ,, 



The Albinos, numbered from 1 to 14, are all from one brood. 

 The following are the results of matings between the Spotted 

 Albinos and Pure Reds : — 



20. Male carrying Black 63 unspotted young and 1 spotted 



77. Female ,, Black and Bed 51 ,, ,, 2 „ 



78. Female ,, „ ,,10 „ ,, 1 „ 

 80. Male „ Black 39 „ ,, 3 „ 

 82. Male „ ,, 69 „ ,, 5 ,, 



96. Male ,, „ 105 ,, „ 6 ,, 



97. Female ,, Black and Bed 29 ,, „ 11 „ 



