魚類

A few cases which may be reg arded as mimicry in fishes are reported here. (1) Dead leaf mimicry. Young Platax Pinnatus (Linne) ( Platacidae ) of about 25 ? 50 mm as well as young Lobotes surinamensis (Bloch) (Lobotidae) of about 30 - 80 mm in total length were observed to drift motionless in an oblique posture or horizontally lying on one side among the fallen leaves of the oak and the camphor tree floating on the water surface or hanging obliquely in the water near the shore. The shape, coloration and attitude of these fishes closely resembled the leaves around. ( 2 ) Drifting bark mimicry. Young Canthidermis rotundatus ( Proce )( Balistidae ) of about 20 - 60 mm in total length were observed drifting among the pieces of the pine bark gathered in a rocky chasm of the shore. The dark brown coloration, coarseness of the body surface, the irregularly looking outline of the body as well as the horizontal . posture seemed to emphasize the mimicking effect. Young Lobotes surinamensis of the comparable size were seen in a similar condition. ( 3 ) Drifting pumice-stone mimicry. Young Diodon holacanthus Linne ( Diodontidae ) of about 20 ? 50 mm in total length were found among the pumice-stones drifting near the shore. The fish laid backward their spines which covered their bodies, resembling the rounded pumice-stones in shape, and the grey coloration and motionless attitude seemed to strengthen the mimicking effect. Young Canthidermis rotundatus of nearly the same size were also seen there, lying on one side in horizontal posture and with grey coloration, apparently mimicking the pumice-stones around.