PARKER.—LOCOMOTIQN OF CHITON.
,
foot of an inverted chiton a rigid body with an area ve millimeters
»
square is applied, the animal can attach itself to this area with suf—
cient strength to allow its weight to be lifted.
The fact that chiton
_
can thus suck locally with its foot makes it clear how this mollusk
,
'
,
can
adhere firmly to
sheet of glass from which under
.
like circumstances a crepidula would dislodge itself (Parker, 1911,
'
p. 159).
-
’
'
Chiton tuberculatus exhibits, in addition to its ordinary locomotor
movements, certain unusual.f0rms of motion. ' By swinging the ati-_
teri0r portion of the foot to one side and the posterior portion to the '
other, the animal can rotate its body with the middle of its foot as a
pivot.
When the animal is vigorously stimulated unilaterally, as,
_
for instance, by the application of dilute acetic acid to one side of the
shell, the whole foot, as seen through glass, can make a purely lateral
movement apparently by a single wave that sweeps through the foot
'
sidewise.
Finally, chiton can reverse its locomotion and creep back—
ward a few millimeters.
The motion is never considerable in amount
and is often combined with a lateral movement, but it is unmistakably ,
backward.
So far as I know, this is the rst instance of backward.
locomotion to be recorded in gastropods. Because of the hifrequency
of its occurrence, I was unable to make out the kind of locomotor
_
_
wave by which it was produced
_
‘
_
‘
,
,
-
7
REFERENCES.
'
Parker, G. H.
,_
_
'
1911.
The 1\Œechanism of Loconiotion in GastrOpods. Joui‘n.
'
'
1\Œorph., vol. 22, pp. 155—170.
,
.
,
'
…
Vlès,-F.
_i
…
_' —_
-
1907.
Sur les ondes pedieuses des Mollusques'1'eptateui's;
'- Coinpt. .
-
rend. Acad. Sci., Paris, tome 145, pp. 276—278. . j
.
,
=
(
.
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*