GENERAL VORACITY OF FISHES. 45 



are mingled with the venous blood which is flowing 

 towards the heart, from whence it is pushed to the 

 branchiae, in which, coming into contact with the 

 water, it is converted into arterial blood, and then 

 proceeds to the nourishment of the whole body. 



Fishes are in general extremely voracious, and 

 the rule of " eat or be eaten," applies to them with 

 unusual force. They are almost constantly engaged 

 either in the active pursuit or patient waiting for 

 their prey, their degree of power in its capture 

 depending of course on the dimensions of the mouth 

 and throat, and the strength of the teeth and jaws. 

 If the teeth are sharp and curved, they are capable 

 of seizing and securing either a large and fleshy 

 bait, or the slenderest and most agile animal ; if 

 these parts are broad and strong they are able to 

 bruise the hardest aliment ; if they are feeble or 

 almost wanting, they are only serviceable in pro- 

 curing some inert or unresisting prey. Fishes in- 

 deed, in most instances, shew but little choice in 

 the selection of their food, and their digestive 

 powers are so strong and rapid as speedily to dis- 

 solve all animal substances. They greedily swal- 

 low other fishes, notwithstanding the sharp spines 

 or bony ridges with which they may be armed ; 

 they attack and devour crabs and shell-fish, gulping 

 them entire without the least regard to the feelings 

 of their families ; they do not object occasionally 

 to swallow the young even of their own species, and 

 the more powerful kinds carry their warfare into 

 other kingdoms of nature, and revel on rats, reptiles, 

 and young ducklings, to say nothing, gentle reader, 



