Coloration of Marine Animals. 237 
or white. Some may consider, however, that such is a provision 
for reducing the numbers of troublesome fishes. At any rate 
the view that the pale under surface is protective meets 
with exceptions in those forms. Again, the conspicuously 
pigmented fins of the young mackerel midges (Motelle) can 
scarcely be for protection, unless they mimic spines when 
collapsed, and the same may be said of the yellow pelvics of 
the young ling. Mr. Beddard thinks the bright colour and 
large size of the fins of certain fishes may be protective (e. g. 
flying gurnard), Another example is the sapphirine gurnard, 
yet in this case the protective function 1s doubtful. 
The transparent pelagic eggs of the cod tribe, flounder 
tribe, and many others are supposed to escape notice by this 
provision, but then the young becomes conspicuously tinted 
before hatching, and therefore at a time when it is most 
important that it should be invisible. If translucency be a 
protection in the one case, colour under the same circum- 
stances cannot likewise be so. 
The very great variety of markings and tints in larval 
fishes under the same conditions shows the difficulty of 
drawing rigid conclusions as to protective or warning colora- 
tion in such forms, though they may be remnants of ancestral 
coloration. Some might be disposed to think this a crucial 
test of the theories propounded concerning the environment 
of certain forms on land. Yet the history of the changes of 
coloration undergone by a single species, e. g. the cod, shows 
that important purposes are subserved by these changes. 
Thus the minute larval cod escapes from the egg with a series 
of transverse bars; then the black pigment is rearranged 
longitudinally along the dorsum as it swims high in the 
water. ‘To this is by-and-by added yellow pigment, causing 
(with the black) a greenish hue. When it seeks the rocky 
margins it becomes boldly tessellated. At a later stage it 
again becomes more uniformly tinted as it seeks the offshore, 
though some which haunt the tangle-forests are boldly 
blotched with reddish brown. In its adult state its sides and 
dorsum are mottled with yellowish green, though this does 
not seriously affect its uniformity. If we attempt to contrast 
the foregoing changes with those of the haddock, uncertainties 
arise. ‘lhe larval haddock has no transverse bars, though 
bred side by side with the cod, but the dorsal band of black 
pigment is developed in the next stage (post-larval). Instead 
of seeking the shore the little haddock keeps to deep water, 
and it soon develops the characteristic bold touches of black 
on the sides above the pectoral region, the rest being uniformly 
Ann. & Mag. N. Hist. Ser. 7. Vol. vii. 17 
