The Life of CrustaceaCalman, W. T. (William Thomas)
Science
The Life of Crustacea
Calman, W. T. (William Thomas)
Crustacea
The relative importance of the various senses in the Lobster is well
illustrated in the following account of its habits given by Dr. H. C.
Williamson in the Report of the Scottish Fishery Board for 1904. After
noticing that, in daylight at least, the Lobster appears to be
"purblind," only distinguishing light from shadow, Dr. Williamson goes
on: "It tests a shadow with its antennæ, or sometimes, when a strong
shadow is thrown on it, it jumps at it with its chelæ outstretched and
snapping. It is dependent on its antennæ for guiding it in safe places.
It is especially careful in testing any hole before it is satisfied with
it. It discovers the cavity by means of its antenna, which is waved well
out to the side and in front as it walks. It searches the innermost
depths of the hole with the antenna, and then inserts its chela. If the
examination with the chela is also satisfactory, it immediately turns
and backs smartly into the hole. In feeding it is guided to the food by
the antennules. A piece of food which is dropped near a Lobster may fall
quite unnoticed unless it happens to touch the antenna or the [legs].
It is not seen at all. But sooner or later, according as the distance is
short or great, the scent of the food, carried by the currents set up by
the exopodites of the maxillipeds, reaches the Lobster. The Lobster is
immediately excited, although previously it was lying quite inert in its
hole. It whips the water with its antennules in a staccato fashion, and
feels about with the antennæ and chelæ, at first without leaving its
hole. At once both antennules are seen to be whipping in the direction
in which the food is lying, and an active search is made with the
antennæ. If they do not succeed in locating the bait, the Lobster rather
reluctantly leaves its hole, but cautiously, feeling all round about
with its antennæ. It goes off straight in the direction in which the
food is lying, and, if it misses it with its antennæ and chelæ, walks
over it and gets it with its chelate [walking legs]; it usually picks up
its food with the second [walking leg]. Meanwhile the expected feast has
by association stimulated the maxillipeds, which are actively working as
if they were already masticating the food. Once the food is seized it is
conveyed to the maxillipeds, and the Lobster retreats to its hole, there
to enjoy its meal."
Public-domain text, read in full here on John Shaqi.
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