30 THE ANIMAL KINGDOM, 



CHARACTERS 



OF THE 



CLASSES OF THE ANIMAL KINGDOM. 



I. MAMMALIA. 



The heart has two auricles and two ventricles ; the blood is warm and red. 



The lungs refpire regularly alternate. 



The jaws are horizontally incumbent on each other, and covered with lips ; within 

 •which the teeth are, for the moil part, included. 



They procreate by an intrant penis ; are viviparous and la&iferous. 



Their organs of fenfe are, the tongue, noft rils, eyes, ears, and the cutaneous pa- 

 pillae. 



They are covered with hair ; which is thin on the animals of the warmer regions, 

 and very fcanty on aquatic animals. 



Their motive organs are four legs and feet; except thofe which are entirely con- 

 fined to the water, whofe hind legs are wanting. Molt have tails. 



II. BIRDS. 



The heart has two auricles and two ventricles ; the blood is warm and red. 

 The lungs refpire regularly alternate. 



The jaws are horizontally incumbent, naked, flretched out, and without teeth. 

 The penis is fubintrant; they have no fcrotum; and are oviparous, the eggs being 



covered with a calcareous fhell. 

 Their organs of fenfe are, the tongue, noftrils, eyes, and ears, without external 



auricles. 

 They are covered with incumbent, imbricated feathers, lapping over each other like 



flates on a roof. 

 Their extremities are, two legs and feet, two wings, and a heart-mnped rump. 



III. 



