FISHES 147 



endings causing the secretion of a substance called 

 " neurohumor," a substance which is secreted in a range 

 of two opposing systems, the one spreading the pigments 

 through the cellular processes, the other causing them to 

 contract. 



The scientific side of the colour formation will commend 

 itself necessarily to a restricted audience, but the actual 

 effects as demonstrated in public aquaria make a general 

 appeal. Often these colour phases arrange themselves 

 in certain definite patterns, and in the past such examples 

 sometimes became the subject of strange myths and 

 superstitions. 



Thus even to-day the dark spherical markings on the 

 side of the John Dory (Zeus faber) are pointed to as com- 

 memorating the occasion when Saint Peter took the fish 

 between the thumb and forefinger when extracting the 

 tithe money. 



In a species of Butterfly Fish common off the Zanzibar 

 coast, certain markings on the tail fins suggest old Arabic 

 characters, and some years ago these were so pronounced 

 in a certain specimen that they actually spelt " Laillaha 

 illalah " and " Shamiallah," i.e., " There is no god but 

 Allah,'' and " The warning sent from Allah." This fish, 

 normally worth only a penny in the native fish markets, 

 was purchased for 5,000 rupees. 



A quaint Arabic legend attaches to the colouring of the 

 Flatfishes, which, as is well known, are pigmented on one 

 side only. According to the native story, Moses was 

 cooking a Flatfish when the oil suddenly gave out. The 

 irritated patriarch flung the half-browned fish into the 

 sea, where it came to life and handed down its peculiar 



