LECTURE I. 11 



The great or gnu-mi Linn;van outline or ar- 

 rangemt nt of the animal world is thus distributed. 



First, into such animals as have warm ml blood, 

 and a heart di\id<d into two ca\ it ies, or ventricles, 

 ;ts anatomists term them. These animals consist 

 of Quadrupeds and Birds; the former being vi- 

 viparous, or producing living and ready-formed 

 voung, and the latter or birds being oviparous, or 

 producing eggs, from which the young are after* 

 wards excluded. 



The next division consists of such animals as 

 have a heart with a single cavity or ventricle, 

 while the blood, though red, is of a far lower tern- 



iture than in quadrupeds and birds; insomuch 

 that it is commonly said to be cold blood. These 

 animals consist of what Linnaeus calls Amphibia, 

 such as Tortoises, Frogs, Lizards, and Serpents, 

 and in the next place, of Fishes. The former of 

 these subdivisions, or the Frog, Tortoise, Lizard, 

 and Serpent tribes, have what Linnaeus terms ar- 

 bitrary lungs, or such as can suspend respiration 

 at pleasure, for a considerable time, without injury 

 to the animal. The latter tribe, or that of Fishes, 

 instead of lungs, is furnished with what are 



