222 THE OCEAN. 
returning through the left auricle and ventricle, is 
thrown into the right ventricle, and mixed with that 
which is just brought from the body; the mixed 
blood being partly returned to the body through the 
aorta, and partly sent to the lungs. But this is the 
course only when the animal is breathing; and as a 
large part of its life is passed under water, this con- 
trivance enables the circulation to go on under cir- 
cumstances when breathing necessarily ceases. For 
if no air enters the lungs, the blood cannot pass 
through them; therefore, when under water, the 
blood passing through the right auricle and ventricle, 
is immediately sent by the aorta into the body with- 
out any exposure to the air. Of course, as the blood 
thus unrenewed would become more and more im- 
pure, this could not proceed very long without loss 
of life, and hence there is a limit to the period 
during which the breathing may be suspended, when 
the animal must come to the surface or die. 
Many of the fishes of these seas partake of the 
brilliancy of colour with which the birds and insects 
of the same sunny region are so lavishly adorned. 
J have seen some of great beauty readily captured 
with a hook from the deck of a vessel in shallow 
water ;—such as the Yellow-fin (Sparus synagris, 
Lryw.), which has its body marked with longitudinal 
bands of delicate pink and yellow alternately; the 
fins are bright yellow, and the tail fine pale crimson. 
A larger species, which the seamen denominated the 
Market-fish (Labrus anthias, L.), is all over of a 
silvery tint with a ruddy glow, the fins and tail 
bright crimson; this species has very large scales. 
