New-York tribune., 1905-12-24

While the animals eyes appear to be large
and normal those of allied terrestrial spe-
cies in reality its sense of sight seems to be ex
tremely limited. When discovered it remains
quiet and shows little fear until touched, when
it scrambles deeper into the crevice or beneath
some fallen rock the floor. Even when a
candle IS put within few inches of it's head it
does not move until it feels the heat.
A few years ago the United States Fish
Commission was boring an artesian well at it's
San Marcos. Tex, fish hatchery, a cave stream
about one hundred and ninety feet below the
surface was tapped From this stream was
taken a number of specimens OF a new species
of the true cave salamander. They were small
and colOrless, and the only signs that they ever
possessed organs of vision We're two little black
spots above the nostrils. The animal seems to
be fairly common in the vicinity OF San Marcos
as 1t has been found in several caves and under
ground streams in that vicinity. similar rep
tile, known the ohm. inhabits Austrian cave
rivers. 1t is especially abundant in the depths
Of Planina Cave, nearly a mile and a half from
the entrance, the waters being fairly alive with
them.
are occasionally found. The most noted is that
of the blind crayfish of the cave regions Of the
Ohio Valley. This animal tnhabits shallow pools
with muddy bottom 1t moves slowly with it's
feelers spread out before it and gently moving
to and fro, feeling, 1t We're every inch Of
its way 1t is wholly non sensitive to light and
seemingly to sound but when disturbed by
any movement in the water It is extremely &C.
tive, much more so than ordinaryt terrestrial
powerful downward blows of its abdomen.
In the Mammoth Cave is found another blind
crustacean (Astacus pellucides). In this animal
the eyes are not entirely wanting for two small
abortiVe eyeStalkS still remain in the position in
which eyes are developed in all normal decapods
One Of the most curious cases of degeneration
amongst the crustacea is that of Ethusa eranu-
lata, one Of the stalkeyed crustacea. In shallow
water It is found with we'll developed eyes
In deeper water, from 11O to $40 fathoms eye
stalks are present, but the animal is apparently
blind, the eyes being replaced by rounded termi-
nations to the stalks: in examples from 500 to
700 fathoms. in another locality. the eyestalks
have lost their special character, have become
fixed, and their terminations combine into G.
strong pointed beak. In this case we have a
gradual modification, depending apparently upon
gradual dininution and final disappearance of
solar light.
The Challenger also dredged three species Of
crustacea between st. Thomas and the Ber-
mudas in which the eyes missing.
In a large number OF marine molluEca which
habituaily creep about half buried IN wet sand
QBullia, Sigaretus, Scaphander. Philine) eyes are
altogether missing. IN species Of Natica
and Sigaretus and in Doris eyes are developed
but inclosed in u thick layer of skin, through
which they probably do little moro than
family appreciate different degrees Of light and
darkness. Chiffon has cephalic eyes IN the en-
bryo, but loses them In the adult stage; this is
a remarkable tendency shown by certain pelagio
species. Deep Inollusca. q rule possess
rudimentary state but this rule has it's excep-
tions. A few species of land mollusca which
live beneath the surface OF the ground or in
caves in absolute darkness are either entirely
or-have them in a. dinentary
state~ ~ y 19-7Y sf~e-s-~zs