Coloration of Murine Aniiniln. 239 



bravery of liis coiispicuoua coloration. Wliy tliesc bright 

 colours are specially developed at the spawtiinj^-seasori 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 s'vallow two of them, the largm- 

 about a foot long. It is interesting that the liimaculate I 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 

 sexes. 



The coloration of the large marine lizxrd [Oreocephilus 

 amhlyrhynchus) 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 capture! 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. Ii^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 wliite. 



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 tjie ducks are boldly separated by the brighter c )lour of 

 the males. 



Shore-birds, again, are usually greyish and less visible in 

 many cases, yet the oyster-catcher is prominently speckleJ. 



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 an 1 others that 

 the Idack and white colours of the dorsum and un ier surface 

 of porpoises have been acquired for protection (on the sam i 

 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, 

 file dark brownish-grey hue of the seals in the water avails 

 them no better, for they are likewise capturdl by the killers. 

 Tlie colour of the larger whales, again, is similar to that of 



17* 



