The Journal of experimental zoology . nguishwhether marked or not. 6/29 12 9 0 Three others seen but inaccessible; marked? 7/ 1 10 8 0 Two others seen but inaccessible; marked? 7/14 9 8 0 specimens. The general result is clear, however: Chiton is notstationary, it does move about to some extent, but adult ani-mals, such as those used in this experiment, do not move fre-quently from place to place. Further observations showed that there is probably somecorrelation with age in the matter of migration. The youngest 180 LESLIE B. ABEY AND W. J. CROZIER animals tend to occur in isol
The Journal of experimental zoology . nguishwhether marked or not. 6/29 12 9 0 Three others seen but inaccessible; marked? 7/ 1 10 8 0 Two others seen but inaccessible; marked? 7/14 9 8 0 specimens. The general result is clear, however: Chiton is notstationary, it does move about to some extent, but adult ani-mals, such as those used in this experiment, do not move fre-quently from place to place. Further observations showed that there is probably somecorrelation with age in the matter of migration. The youngest 180 LESLIE B. ABEY AND W. J. CROZIER animals tend to occur in isolated groups, and further from high-water level than the younger individuals, there results a type ofsegregation which is favorable to the occurrence of some degreeof homogamy (assortive fertilization). This would result in theeconomical utilization of sperms, and might possibly have ad-ditional effects of an adaptive kind. Some further correlationbetween habitat and breeding habits in other chitons have beennoted by Heath (05 c, 07).. [CPH-Pop(s,pKoto-3 Fig. 9 A group of Chitons in a shallow depression. X h 8. Bionomic correlations Chiton tuberculatus is strictly intertidal in habitat. It, there-fore, becomes possible to examine the details of its naturalhistory rather extensively. The complexity of the catenarysystems of relations revealed by such examination rendersorderly description difficult. Some of these relations we havereferred to in the preceding sections. Numerous others remain THE SENSOKY RESPONSES OF CHITON 181 to be considered. They concern phenomena of coloration, re-production, determination of choice of habitat, and similarfeatures, comprising some of the things which involve explanationin terms of the animals sensory physiology. In the matter ofcoloration, for example, the chitons in general exhibit homo-chromic (concealing) characteristics which are commonly ofsome precision (, in Cryptochiton, Heath, 05 b, p. 213,and in other genera which we have observe
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