CRUSTACEANS OF TIIE CAVE. 
17 
Fir. 131. 
motli Cave, a brownish centipede-like myriopod, over an inch in 
length, which moved off in a rapid zigzag motion. Unfortunately 
he did not capture it. 
Next to the blind fish, the blind crawfish attracts the attention 
of visitors to the cave. This is the Gamharus pellucidus (Fig. 
131, from Hagen’s 
monograph of the 
North American 
Astacidse) first de- 
scribed by Dr. Tell- 
k a m p f . He re- 
marks that “the 
eyes are rudiment- 
ary in the adults, 
but are larger in 
the young.” We 
might add that this 
is an evidence that 
the embryo devel- 
ops like those of 
the other species ; 
and that the inher- 
itance of the blind 
condition is proba- 
bly due to causes 
first acting on the a- 
d lilts and transmit- 
ted to their young, 
until the production 
of offspring that be- 
come blind becomes 
a habit. This is 
a partial proof at 
least that the char- 
acters separating 
the genera and spe- 
cies of animals are 
those inherited from adults, modified b}^ their physical surround- 
ings and adaptations to changing conditions of life, inducing cer- 
tain alterations in parts which have been transmitted with more or 
MAMMOTH CAVE. 2 
