736 The American Naturalist. [September, 
states, regarding the blind Cambarus of the Missouri Cave: 
“ Very young specimens of C. setosus correspond better with the 
adults of C. bartonii; their eyes are more prominent in these 
stages, and appear to lack but the pigment.” In the blind 
cave-shrimp (Troglocaris) of Austria, Dr. Joseph discovered 
that the embryo is provided in the egg with eyes. 
In this connection should be recalled the observations of 
Semper in his Animal Life (p. 80, 81) on Pinnotheres holothuriae, 
which lives in the “ water-lungs” of Holothurians, where, of 
course, there is an absence of light. The zoéa of this form has 
large, “ well-developed eyes of the typical character. Even 
when they enter the animal, they still preserve these eyes; but 
as they grow they gradually become blind or half-blind, the 
brow grows forward over the eyes, and finally covers them so : 
completely that, in the oldest individuals, not the slightest 
trace of them, or of the pigment, is to be seen through the 
thick skin, while, at the same time, the eyes seem to undergo à 
more or less extensive retrogressive metamorphosis." 
In this connection may be mentioned the case of the burrow- 
ing blind shrimp (Callianassa stimpsonii) which has been found 
by Professor H. C. Bumpus, at Wood's Holl, Mass., living in 
holes at a depth of between one and two feet. He has kindly 
given me a specimen of the shrimp, which is blind, with 
reduced eyes, smaller in proportion to the body than those of 
the blind crayfish. He has also obtained the eggs, and has 
found that the embryos are provided with distinct, black, pig- 
mented eyes, which can be seen through the egg-shell. 
Recently, Zeller has studied the embryology of the Proteus 
of Adelsberg Cave, and has confirmed the statement of Micha- 
. helles, who, in 1831, discovered that the eyes of this animal 
are more distinct in the young and somewhat larger than in 
the adult. We quote and translate from Zeller's acecount : 
“The development of the eyes is very remarkable; they are 
immediately perceived and present themselves as small, but 
entirely black and clearly drawn circular points with a slit 
which is very narrow and yet, at the same time, well-defined, 
and which penetrates from the lower circumference out to the 2 
middle. 
