conclude as to the alertness of their senses? Does the covering of its body suggest the possession of a delicate or dull sense of touch?
Of what motions are the eyes capable? Touch one of the eyes. The result? Can a crawfish see in all directions? To test this, place a crawfish on a table and try whether you can move to a place where you can see the crawfish without seeing its eyes. What are the advantages and disadvantages of having the eyes on stalks?
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Fig. 81.—Crawfish (dorsal surface).
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Fig. 82.
Touch the body and the several appendages of the crawfish. Where does it seem most sensitive to touch? Which can reach farther, the antennæ or the big claws? Why are short feelers needed as well as long ones?
Make a loud and sudden noise without jarring the crawfish. Is it affected by sound?
External Anatomy (Figs. 81, 82, 83, 84).—Is the body of the crawfish rounded out (convex) everywhere, or is any part of its surface either flat or rounded in (concave)?
