LOSS OF EYE-PIGMENT IN GAMMARUS. 33D 
tion. Adding together all the figures for the young obtained from all the 
matings of this generation we have a total of 600 distributed as follows :— 
Normal Red Normal Colourless (Albino 
Red. No-white. Albino. No-white). 
PURE ORY: see eed a 2 338 112 112 38 
Experiment ....... 346 iL 105 38 
Black with Red. 
Fig. 3 (Plate VI) shows the result of mating together a black and a 
red offspring (Plate III, Fig. 6, 11.D.1.j.1.) of Albino carrying black and 
red crossed with Red No-white. See Parent Generation | (A+ B+R >» 
RN). 
In this case theory requires that out of 32 young, 9 should be normal 
blacks, 9 normal reds, 3 black no-whites, 3 red no-whites, 6 normal 
albinos and 2 colourless (albino no-whites). 
Fig. 3 shows the first 5 broods with a total of 100 young, the theoreti- 
cal and experimental numbers for the categories being :— 
Normal Black = Normal Red Normal pees 
Blacks. No-whites. Reds. No-whites. Albinos, (Albino No- 
whites). 
MOR ys. 57. 5 28 9 28 9 18 6 
Bxperment .. 28 15 30 4 20 3 
Since the plate was made further broods have been obtaimed, and the 
total number of young is 491, distributed as follows :— 
Normal Black Normal Red Normal Colourless 
Blacks, No-whites. Reds, No-whites. ‘Albinos, (Albino No- 
whites). 
IRRCOTY. 3 ¢.<56025 138 46 138 46 9? 30 
Experiment .. 109 So 157 45 104 23 
F.1. Generation from A+B RN. 
The young belonging to this generation were mated together and pro- 
duced 434 young, classified as follows : — 
Normal Black Normal Red Normal Colour! cas 
Blacks. No-whites. Reds. No-whites. Albinos. (Albino No- 
whites), 
heory sis. 5\<7: 184 61 61 20 82 27 
Experiment .. 164 60 66 27 94 23 
F.1. Generation from A+R RN. 
The young belonging to this generation were mated together and pro- 
duced 220 young, classified as follows :— 
Red. Red No-white. Albino, Albino (Colcurless) 
No-white. 
BG ON Sistas ee Sake 2c 124 41 41 14 
Experment, -:.. ... 127 38 42 13 
