533 
THK OCEAN WOULD. 
( Aeanthius ), which it meets with in its wanderings. Its adhesion to 
those objects is so strong that the strength of a man fails to separate 
them. It sometimes attaches itself to the belly of the shark, and 
makes long voyages on this monstrous locomotive animal, and that 
without fatigue or danger, for its enemies are kept at a distance by the 
formidable monster which carries it. 
II. PLEUKONECTIDiE. 
The Flat-fishes ( Pleuronectidx ) have the body flat and greatly 
compressed, but in a direction different from that of the Baias and 
other analogous beings. In the case of the Eaia the body is flattened 
horizontally, while in the Pleuronectidae they are compressed laterally. 
The head of fishes of this order is not symmetrical ; the two eyes are 
placed on the same side ; the two sides of the mouth are unequal. 
To these peculiarities of structure we shall return when we come 
to observe the several types more clearly. In inaction, as in motion, 
the flat-fishes are always turned upon their side, and the side turned 
towards the bottom of the sea is that which has no eye. This habit of 
swimming on their side is that to which they owe then name of 
TrXevpa, side, and ue^rov, swimmers. 
Their chief organ of natation is the caudal fin, but they are distin- 
guished from all other fishes by the manner in which they use this 
oar. When turned upon their side this organ is not horizontal, but 
vertical, and strikes the water vertically up and down, They advance 
through the water but very slowly, compared to the motion of other 
fishes. They ascend or descend in the water with greater promptitude, 
but they cannot turn to the right or left with the same facility 
as other fishes. This property of rising or sinking in the water with 
facility is the more useful to them inasmuch as the greater part of 
their existence is passed at the greatest depths, where they draw 
themselves along the sands at the bottom of the sea, and often 
hide themselves from their enemies. Among the Pleuronedidse, 
soles, turbot, flounders, and plaice may be noted. 
Soles (i Solea) have the body oblong, the side opposite to the edges 
generally furnished with shaggy, soft hairs ; the muzzles round, nearly 
always in advance of the mouth, which is twisted to the left side, 
and furnished with teeth on one side only, while the eyes are on the 
