[ 18 
Experiments on the Mendelian Inheritance of Eye- 
colour in the Amphipod Gammarus cheureuxi. 
By 
E. W. Sexton, F.LS., 
Marine Biological Laboratory, Plymouth, 
AND 
M. B. Wing. 
With Plate I. 
CONTENTS. 
yeneral conditions—habits, water, air, food, light 
Explanation of terms employed in paper : f 4 : ; : 
The pigmentation of the eye—black, red, “ all-white,” “* part-white,” and ** no-white ” 
The first appearance of the Red eyes 
Results of examinations of dredgings : 
Experimental work—question of sex-limitation . 
I. Recessives to the sixth generation 
JI. Dominants—Pure Blacks : 
Proportions of P. and H. 
Hybrids—Parent generation 
F, generation 
*, generation 
K, M, and N families 
Proportions of Black and Red 
Proportions of Pure and Hybrid 
Table of results 
Preponderance of colour 
Results of Black crosses 
Sex of survivors 
Records of Abnormal Eyes. : : : 
General notes—breeding different generations, etc. 
Summary 
PAGE 
19 
21 
26 
30 
31 
THE Amphipod which was used in the following experiments was described 
in 1913 (Journ. M.B.A., Vol. IX, pp. 542-545) under the name 
of 
Gammarus chevreuxi, and its life history was then worked out (see Sexton 
and Matthews, l.c., pp. 546-556). 
The usual colour of the eye in this species, as in the other species of 
genus Gammarus, is black, but several females and young with red e 
the 
yes 
were observed while the above work was in progress. Beyond recording 
