TRANSMISSION OF INDUCED EYE-DEFECTS 205 
line, both by mating back to 3A1 and by mating to another de- 
fective-eyed male (figs. 6 and 7). 
To return to the 4A series, some of the females of which had 
meanwhile been bred back to 3A1 or to their brothers. On 
April 26, 1918, 4A5 (left eye defective) produced six young sired 
by 4A8, a normal-eyed brother (fig. 5). Two died immediately. 
' Of the remaining four (6A series) three were females; 6A2 (pl. 
1) had colobomaand opaque lensesin both eyes; 6A3 had coloboma 
in the right eye only and the lens had an opaque rim; in 6A4 
(pl. 1) the left eye was much smaller with the eyeball rotated 
toward the front leaving only a small part of the pupil visible 
through which an opaque lens could be seen. In 6A1, (pl. 1), 
the male, each eye had coloboma and an opaque lens. 
Next, 445 was bred back to her father 3A1. From this mating 
four young were born December 28, 1918. In this litter (fig. 5) 
one female, 6B (pl. 4), had a right eye about one-fourth normal 
size and the iris, incomplete toward the corner, did not expand 
or contract; the lens was clouded. The left eye had a normal 
pupillary reflex, but the iris was more translucent than normal 
and the margin of the lens was milky. The eyes of the other 
three were apparently normal. 
Another female, 4A1 (pl. 1), when mated to 3A1 (fig. 5) gave 
birth to five young June 21, 1918. Of this litter, 10A1 (pl. 1), 
a female, had coloboma and an opaque lens in the left eye, while 
the right eye outwardly normal contained a slight flaw in the 
lens; 10A2 (pl. 1), a male, had the left eye similar to 10A1 except 
for a larger pupil, and the right eye very small and peculiar in 
color; 10A3 (pl. 1), a female, had both eyes small with irises in- 
complete and lenses clouded; 10A4 (pl. 1), a male, had eyes like 
10A3 until he was half grown, but later the left eye collapsed so 
that no detail could be made out in it; 10A5, a male, with eyes 
apparently normal had the hind legs completely paralyzed and 
died on August 19, 1918. However, it should be noted that the 
eyes of 10A5 were never examined with the ophthalmoscope and 
such examination has revealed cloudy or flawed lenses in some 
eyes which outwardly appeared normal. 
