LOSS OF EYE-PIGMENT IN GAMMARUS. 279 
IJ.D. Female, Black carrying Albino only (Plate IT). 
Matings :—(1) with male A of the same brood (89 young, 
66 Black, 23 Albino).* 
II.A. Male, Black carrying Red and Albino (Plate I). 
Mating: (1) with female K of the same brood (B+R-+- 
A); 61 young, 30 Black, 14 Red, 17 
Albino. 
III.B. Male, Black carrying Albino only (proof obtained by mating the 
offspring). 
Matings : (1) with female L of the same brood (B+-A) ; 
33 young, 20 Black, 13 Albino. 
The first brood of this pair were mated together, and also with 
Red mates ; the resulting young numbered 153, 115 Black and 38 
Albino (see Pl. III, Fig. 3, for an example). Black young of the first 
brood of these were mated together, and gave 19 Black, 3 Albino ; 
mated with Reds they gave 52 young, all Black. 
According to these matings both male B and female L are Blacks 
carrying the Albino factor only. 
II1.C. Male, Black carrying Albino only (probably). 
Matings :(1) with female M of the same brood (B+ A, 
Red factor not known); 78 young, 57 
Black, 21 Albino. 
One of this pair is certainly a (B+ A), the constitution of the other 
is not known. 
III.D. Male, Black carrying Albino only. 
Matings :—(1) with female N of the same brood, (B+ A) ; 
115 young, 78 Black, 37 Albino ; 
(2) with female VI.B.2.e. (R-+A); (19 young, 
11 Black, 8 Albino) ; 
(3) with female IV.X. (R+<A); 429 young, 
329 Black, 100 Albino. 
III.E. Male, Black carrying Albino. Red not proved. 
Matings :—(1) with female O of the same brood, (B+ 
R+ A); 5 young, 4 Black, 1 Albino. 
IIL.F. Male, Black carrying Albino only (probably). 
Matings :—(1) with female P of the same brood; 69 
young, 53 Black, 16 Albino. 
One of this pair is certainly a (B+ A), the constitution of the 
other is not known. 
* Figures between brackets are also given under the other member of the pair and 
must therefore not be included in the totals. 
