3 o PATTERNS ON LIVING ANIMALS 
delicately formed that its body offered a scarcely 
greater obstacle to the passage of the sunlight than 
the water in which it swam, was decorated on either 
side by one, or sometimes two, of those exquisite 
ornaments seen in the greatest perfection in the train 
of the peacock, which are perhaps best described as 
the “peacock-eye.” It was no mere spot, lying in a 
ring of a different colour, such as decorates the sides 
of a trout or salmon, but a perfectly-developed pea- 
cock-gem, lying in its gorgeous rings of blue, green, 
and gold, equally rich and dark in tint, and even more 
striking from its contrast with the colourless and semi- 
transparent body of the creature it adorned. The 
analogy with the pattern on the peacock’s tail was 
even more complete than that which a first glance 
disclosed ; for on many of the fish a third or rudi- 
mentary eye appeared, fainter and elongated, like a 
smudge of wet colour, and corresponding exactly with 
the gradation or evolutionary process of ornament, 
which Charles Darwin noted in the side-feathers of the 
peacock-train. This wonderful decoration, which was 
assumed, like the brilliant red and emerald of the 
English sticklebacks, for the period of courtship only, 
disappears later in the year ; and the creatures abide 
in plain clothes till next spring. But the character of 
the ornament they wear suggests a further and separate 
interest, beyond that which their beauty naturally 
claims. Pattern , by which we mean the repetition of 
certain and regular forms, so as to produce an orna- 
ment which pleases the eye without making any 
