364 TH, di AMID INTE 
wrinkled, which also is recessive. That these factors are actually present 
can be proved by continuing the experiment to the next generation. 
Similarly the yellow wrinkled and the green rounds are not all the same- 
PEAS 
YELLOW\CROSSED witH GREE 
WRINKLED! ROUN 
P Zyc. Ma eae 
P cam YW GR 
F |. Zycote 
YW YR GR GW Eemate 
Fl. cam. YW YR GR GW mate 
mail 
Ze AW YR) GR GW 
ec) QA) (ee) Bs 
ay} 2G) GH] EY 
Totar SYELLOwW ROUND ~' 
FoR F2 3 YELLOW WRINKLED 
3 CREEN ROUND 
| GREEN WRINKLED 
DIAGRAM D5. 
In the case of the green wrinkled, on the other hand-—the double 
recessive-—one constitution only occurs, and these peas would all breed 
true for however many generations the breeding were continued. 
From what has been said already you will I hope have got a clear idea 
of the simple law, first enunciated by Mendel, which often governs the 
hereditary transmission of characters from parent to offspring. I propose 
now to communicate to you some results of the study of a particular 
instance of Mendelian inheritance, which has been worked out during the 
last two or three years in connection with the Marine Biological Labor- 
atory. One paper, describing the earlier portions of the work, has been 
published already in the Journal of the Marine Biological Association, 
bearing the title “‘ Experiments on the Mendelian Inheritance of Eye- 
colour in the Amphipod Gammarus chevreuxt, by KE. W. Sexton and M. B. 
Wing.” I have now in preparation a further paper (see page 273 of this 
Journal) dealing with the later investigations, the experimental work 
connected with which has been carried out by Mrs. Sexton.* 
“ Sexron, E. W., and WinG, M. B. Experiments on the Mendelian Inheritance of Eye- 
colour iu the Amphipod Gammarus cherreuxi. Journ. Mar. Biol. Assoc., XI, p. 18. 1916. 
ALLEN, E. J., and Sexron, li. W. The Loss of the Eye-pigment in Gammarus: 
chevreuri, Journ. Mar. Biol. Assoc., XI, p. 273. 1917. 
