54 
SPOLIA ZBYLANICA. 
resemble, as I said before, a waterlogged oak leaf. None of the 
jetty fishermen had seen such a fish before, and until I was with 
you to-day I had some slight hopes that I had added one more fish 
to my credit as new to science.” 
When the fishes are taken out of water they lose to a certain 
degree the strangeness of their appearance, and when they are 
preserved the fins collapse and contract, so that even the best 
drawing will fail to catch the living aspect of the animal. The 
individuals observed by Mr. Gordon-Smith appear from his 
account of their defective movements to have been in an abnormal 
condition, unable to progress in a definite direction or to flee from 
the wrath to come in the shape of their captors. So far as can be 
judged, they presented the symptoms of fishes disabled by the 
concussion of dynamite. The probability that they had been 
suffering in some particular rather detracted from their bionomical 
interest, and rendered any theoretical deduction based upon their 
fancied resemblance to a faded leaf, impracticable. 
Under these circumstances I was very pleased indeed to have 
the opportunity of seeing for myself the peculiar movements of a 
Plcctax vespertilio under perfectly normal conditions inside the 
reef at Beruwala in February of this year. I was walking along 
the reef in the company of a fisherman carrying a net when he 
espied a small fish, which he attempted to catch for me. I could not 
see what it was at first, but noticed that the man failed to bag it 
after several ineffectual attempts. The fish did not swim far away 
from the spot, but dodged about baffling its pursuer. I approached 
and seized the net, whereupon I saw a yellow jak leaf gently and 
inertly sinking to the bottom. This is surely no unusual sight 
close inshore, and I was about to turn away, when to my astonish¬ 
ment the leaf righted itself and darted away. Efforts were then 
redoubled and the fish secured and subsequently I sketched it 
alive to show as far as possible its natural contour. 
When a fish has a leaf-shaped and leaf-coloured body and in 
addition has the unique habit of toppling over and feigning death 
when pursued, it seems natural to conclude that it is a genuine 
example of protective resemblance. 
Under water the general contour of the fish is almost identical 
with that of the leaf-butterfly when resting with closed wings. 
The contour along the posterior border is strengthened by a dark 
line of pigment along the margin of the dorsal and anal fins passing 
across the base of the tail fin. The tail fin itself is unpigmented, 
perfectly transparent, and consequently invisible under water. The 
pectoral fins are also transparent, but the elongated ventral fins are 
opaque, showing the yellow ground colour and a dense outer border 
