64 MIMICRY AND HOMOPLASY 



Phyllopteryx, of which there is a figure in Dr 

 Giinther's " Study of Fishes " (1880), is furnished 

 with cutaneous processes which resemble trailing 

 seaweed. Another fish, during a limited period 

 of its life-history, namely, about the yearling 

 stage, effectively resembles a dead water-logged 

 leaf. This is the young of the so-called sea- 

 bat, Platax pespertilio} The mature fish is 

 nearly uniformly dark-coloured ; it attains a 

 moderate size and is very high in the body, 

 which is strongly compressed. It swims about 

 in small shoals and has the habit, possessed by 

 many other similarly constituted fishes, of turning 

 over on one side momentarily whilst swimming. 

 In the young stage, when the total height of 

 body and fins is about two or three inches, 

 the colour is pale yellowish or brownish with 

 variegated, irregular and variable markings. 

 When seen living in the water, its resemblance 

 to a sere leaf is extraordinary ; when taken out 

 of water it loses something of the strangeness 

 of its appearance, and when preserved, the fins 

 collapse, thereby destroying the living aspect of 

 the animal. 



In February 1904 I had the opportunity of 

 seeing the peculiar movements of a young Platax 

 under normal conditions, off the west coast of 

 Ceylon. Whilst a fisherman was attempting to 

 catch it with a pole-net, it suddenly toppled over 



1 A. Willey, " Note on Leaf-Mimicry," Spolia Zeylanica, vol. ii., 

 1904, pp» 51-55. See also Nature, vol. lxxx., 1909, p. 247. 



