NOTES. 
55 
conterminous with the border of the anal fin, thus preserving the 
continuity of the anterior contour. 
It is quite impossible to exaggerate its likeness to a leaf, and it 
is interesting to learn that the native fishermen also recognize the 
similarity by calling the fish koskolaya ,* which means jak-leaf. 
The surface of the body shows lines of pigment and small spots 
such as are seen in a decaying leaf. These are subject to varia¬ 
tions similar to those which occur on the undersides of the wings 
of Kallima and on the wings and body of Pliyllinm. Only a 
careful coloured drawing of the living fish by an artist could do 
justice to its wonderful form. The figures of this species which 
have been published in various monographs completely fail to 
reproduce its essential attributes. 
Other cases of protective resemblance among fishes are known 
and have become classical, but I know of no other instance in 
which the leaf-form has been acquired. The cases of Pliyllium , 
Kallima , and Platax are illustrations of the phenomenon known 
in Germany as convergent evolution and in England as parallel 
evolution. It is a factor of wide application in biology, sometimes, 
as in the preceding instances, easy to recognize, sometimes obscure 
and questionable, but always remarkable and difficult to explain 
otherwise than in a purely formal manner. 
Colombo, March 16, 1904. A. WILLEY. 
It is also sometimes called nonet. 
