Further Observations on the Locomotor System of Medusae . {e) The effects of temperature on the rate of contractile waves are very striking. Forinstance, in a rather narrow strip measuring 28 inches long and 1^ inch wide, the followingvariations in rate occurred :— Temperature of water. Time occupied in passage ofcontractile waves. 26° 32° 42°65° 75°85° 4 ^ Or, adopting again the graphic method of statement, these variations may be repre-sented as follows:— ME. a, J. EOMxVNES ON THE LOCOMOTOE SYSTEM OF MEDUSA. 723 Fig. 13. 26° QOO 42 )P 7
Further Observations on the Locomotor System of Medusae . {e) The effects of temperature on the rate of contractile waves are very striking. Forinstance, in a rather narrow strip measuring 28 inches long and 1^ inch wide, the followingvariations in rate occurred :— Temperature of water. Time occupied in passage ofcontractile waves. 26° 32° 42°65° 75°85° 4 ^ Or, adopting again the graphic method of statement, these variations may be repre-sented as follows:— ME. a, J. EOMxVNES ON THE LOCOMOTOE SYSTEM OF MEDUSA. 723 Fig. 13. 26° QOO 42 )P 75°85° One second. (/) Submitting a contractile strip to slight strains has also the effect of retarding therate of the waves while they pass through the portions of the strip which have been sub-mitted to strain. The method of straining which I adopted was to pass my finger belowthe strip, and then, by raising my hand, to bring a portion of the strip slightly above thelevel of the water. The irritable, or contractile, surface was kept uppermost, and there^-fore suffered a gentle strain; for the weight of the tissue on either side of the fingermade the upper surface somewhat convex. By passing the finger all the way along thestrip in this way, the latter might be gently strained throughout its entire length, thedegree of straining being determined by the height out of the water to which the tissuewas raised. Of course if the strip is too greatly strained, the contractile waves becomeblocked altogether, as described in my last paper; but shortly before this degree ofstraining was reached, I could general
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