Coloration of Marine Animals. 239 
bravery of his conspicuous coloration. Why these bright 
colours are specially developed at the spawning-season is 
still an open question. It has been suggested they may be 
of use occasionally in terrifying other fishes. In the lump- 
sucker the bright colours do not seem to act as a warning, 
for the cod will in May swallow two of them, the larger 
about a foot long. It is interesting that the bimaculated and 
other suckers are often conspicuously coloured. ‘The females 
do not seem to be less conspicuous in order to subserve 
protection for the eggs. In the case of those fishes, e. g. the 
gunnel, which attend the ova the colour is similar in both 
SCXeS. 
The coloration of the large marine lizard (Oreocephalus 
amblyrhynchus) of the Galapagos Islands (500 miles west of 
South America) and of the oceanic turtles present few features 
of moment. The former is of a dirty black colour. The 
water-snakes, which occasionally are captured in sea-water, 
are often boldly banded with blackish grey and white. 
Sea-birds offer few parallels to land-birds in regard to 
protective coloration. The great group of the gulls is more 
or less white and uniformly tinted in both sexes. [xcep- 
tional coloration occurs in the tern-like boatman-bird, which 
has two long pink feathers in the tail, The skuas, which 
have similar ‘aerial habits, are often brown, and so are the 
petrels, whereas the gannets are yellowish white. 
The swimmers, like the auks, puffins, divers, and penguins, 
have the dorsum dark and the under surface whitish or 
greyish, as in the cormorants. Many ducks and geese are 
similarly tinted, while others are white or black. ‘The sexes 
in the ducks are boldly separated by the brighter colour of 
the males. 
Shore-birds, again, are usually greyish and less visible in 
many cases, yet the oyster-catcher is prominently speckled. 
With the exception of the shore-birds, it cannot be said that 
the coloration of sea-birds is protective. 
In connexion with the highest group, that of the marine 
mammals, it has been stated by Mr. Wallace and others that 
the black and white colours of the dorsum and under ' surface 
of porpoises have been acquired for protection (on the same 
principle as already mentioned in the fishes) ; but this distri- 
bution of colour would not avail them against their greatest 
destroyers, the killers, which swim on a level with them. 
The dark brownish-grey hue of the seals in the water avails 
them no better, for they are likewise captured by the killers. 
The colour of the larger whales, again, is similar to that of 
Nhe 
