THE FLAT-FISH. 236 
into elegant contortions and undulations; often it hangs nearly 
perpendicular with the tail near the surface; now and then it 
butts against the side of the vessel with reiterated blows of its 
nose, as if it could not make out why it should not go forward 
where it can see no impediment. Now it twists about as if it 
would tie its body into a love knot, then hangs motionless in 
some one of the ‘lines of beauty’ in which it has accidentally 
paused.” 
The family of the Pleuronectide or Flat-fishes recommends 
itself to our notice as much by the singularity of its form as by 
its usefulness to man. ‘“ The want of symmetry,” says Yarrell, 
**so unusual in vertebrated animals, is the most striking and 
distinctive character of these fishes: the twisted head with both 
eyes on the same side, one higher than the other, not in the 
same vertical line, and often unequal in size; the mouth cleft 
awry, and the frequent want of uniformity in those fins that 
are in pairs, the pectoral and ventral fins of the under side 
being generally smaller; and the whole of the colour of the 
fish confined to one side, while the other side remains white, 
produce a grotesque appearance: yet a little consideration will 
prove that these various and seemingly obvious anomalies are 
perfectly in harmony with that station in nature which an 
animal possessing such conformation is appointed to fill. 
«As birds are seen to occupy very different situations, some 
obtaining their food on the ground, others on trees, and not a 
few at various degrees of elevation in the air, so are fishes 
destined to reside in different depths of water. The flat-fishes 
and the various species of skate are, by their depressed form of 
body, admirably adapted to inhabit the lowest position, where 
they occupy the least space among their kindred fishes.” 
**Preferring sandy or muddy shores, the place of the flat- 
fish is close to the ground; where, hiding their bodies horizon- 
tally in the loose soil at the bottom, with the head only slightly 
elevated, an eye on the under side of the head would be use- 
less; but as both eyes are placed on the upper surface, an 
extensive range of view is afforded in those various directions 
in which they may either endeavour to find suitable food or 
avoid dangerous enemies. Light, one great cause of colour, 
strikes on the upper surface only; the under surface, like that 
of most other fishes, remains perfectly colourless. Having 
