1 82 



THE 7' ROUT 



intermediate tadpole stage, in which they are known 

 as 'alevins.' Attached to them underneath is a kind 

 of bladder nearly as large as their bodies, known as 

 the umbilical vesicle or yolk sac. 



The American fish-culturist, Seth Green, has aptly 

 described it as 'Nature's feeding-bottle.' It contains 

 nourishment in the shape of oil globules, which are alone 

 sufficient to support the infant until it is able to eat. 



The accompanying graphic diagrams (fig. 1 2), taken 



FIG. 12. 



THE LEFT SIDK OF THE FISH. 



A The heart. 



it Main trunk artery. 



C Large vein. 



n Oil globules, only two of which 

 are introduced for sake of dis- 

 tinctness. 



THE RIGHT SIDE OF THE FISH. 



