THE FISHES _ 169 
than in any of the invertebrates. It also differs in its gen- 
eral plan from that of most adult vertebrates, owing to the 
peculiar method of respiration. In almost every case the 
Fie. 105.—Angler or frogfish (Lophius piscatorius). One-tenth natural size.—After 
BASKETT. 
vessels returning from all parts of the body unite into one 
vein leading into the heart, which consists of only one 
auricle and ventricle (Fig. 106). From the heart the blood 
