INHERITANCE OF EYE-COLOUR IN GAMMARUS. 35 
some inherent weakness; im one or two cases broods of eggs were 
laid but not hatched, in others the stronger mate ate the weaker 
one. 
Of the 80 that survived, 22 proved Pure Black, 8 males and 14 females, 
and 58 proved Hybrid Black, 29 males and 29 females. Ten experiments 
were made with P. males, 24 with P. females, 38 with H. males, and 56 
with H. females. 
The details of the experiments are as follows :— 
TABLE 
showing the details of the experiments made with the black-eyed F, 
progeny of one brood of the F, generation of Hybrids, from September, 
1914, to September, 1915, in order to find the proportion of Pure Black 
to Hybrid Black. Theoretically it should be 1 P. : 2 H., but, as has been 
already explained, the results recorded here cannot be considered exact 
owing to the high mortality amongst the immature. 
Experi- Black. Number Byercolour: Number i oe s 
ment of Young of Pure Black or Hybrid Black. 
Number. ¢ @ hatched. Black. Red. Broods. 
Exp. 1 — 2 No results : 9 eaten. 
a ene D No results : Q died. 
Mero = Oy — — -= = No results : 9 died. 
5 4@ 3) - ( No results. 
meee B90) SATE & 2) die “| ps 
eles Serie iGe rip) 35> lA 
rm Ost O25 15 10 2 ie 
Om: S| j No results. 
pe obo, 85} 14 3° Ee 
erie la! ogi) yt © yee 
} (No results. 
a 
Lore © No results : 9 died. 
Seite 5GIh 34 1 299 AE 
Paes i 2 — 2 ie ql 
1S EO oy Ce a} 2. 
Ge ee ors OP)! 98 Aee aa 
Pl sole eat 10 OF ed. 
Lo ,,/ | Eggs laid, not hatched. 
Peale soo Ap Sep! 
» 20a 3] iene results. 
» 206 ,,- — 9 t 9) ie neh 
perene ) SaaS yao, * 99 ee 
Se a - No results: ¢ died. 
22 — @Q - No results: 9 eaten. 
