782 Dr. Francis Ward [June 6, 



card, when seen from under the water in green surroundings, appeared 

 a dull black. 



When Tecdia crassicornis (a red and white anemone) is attached 

 to the under surface of a rock with a green coloration below, the 

 whites of this anemone appear green and the red markings appear 

 dark, so that now the anemone shows a general green coloration with 

 dark markings upon it, which fit in with the dark markings on the 

 stone. 



Many forms of light-coloured marine life are found under shelv- 

 ing rocks. I consider they escape destruction in this position, owing 

 to the fact that they reflect their surroundings. 



Next let us consider the modification of reflection by pigmentation. 

 This is best illustrated in fishes. Until one has observed fish by 

 entirely natural illumination, it is difficult to realize how important 

 a part reflection plays in making both silvery and highly-pigmented 

 fishes inconspicuous. 



The silvery fish does not appear silvery, but red, brown or green, 

 according to the general colour around, and in addition it will reflect 

 upon its body stem for stem the reeds into which it has rushed in 

 order to hide itself. 



As an illustration to show how a highly-pigmented fish refiects 

 light, I show a tench, only sis inches under the water, and it will be 

 seen the dark back appears quite silvery. 



Pigmentation on the back conceals a fish against the bottom, but 

 undoubtedly the important function is to conceal it, for protective 

 and aggressive purposes, from other fish on the same level as itself. 

 I would point out that the same light which is reflected from the 

 sides of the fish, through the eye of the fish, controls the amount of 

 contraction of the pigment cells on the back : thus the reflection 

 from above is correctly modified, and the fish is rendered a uniform 

 shade. But this uniform shade only conceals against a uniform 

 background. 



Thayer has shown in the animal world, how the counter-shaded 

 bird, or beast, without markings, when seen against a patterned 

 background becomes conspicuous, because it interrupts the pattern. 



The same is seen in the fish world, and in illustration I would 

 draw your attention to the appearance of a perch (Percafluviatilis) 

 swimming past a reed bed. 



In the autochi'ome of a brown trout lying under a stepping 

 stone, I show the value of reflection ; here, the back green, and the 

 belly red, as they reflect the stones above and below, are undoubtedly 

 the main factors in concealing this fish, and the markings simply 

 prevent the body from appearing patternless. 



I would next draw your attention to the possible influence of 

 reflection of light, from some forms of marine vegetation, upon the 

 pigmentation of various marine organisms. 



Several red and brown seaweed's seen by transmitted light appear 



