ANIMALS. 11 



its, classification, and habitation of all animals, from man 

 to the lowest of all the tribes. 

 Vertebrata. — The first division of the animal kingdom com- 

 prises animals in whose structure is a jointed backbone, 

 or vertebral column, and includes the following classes, viz. : 



1. Main'mSils. — Animals which produce their young alive, 

 and which nourish them afterwards by suckling. (For 

 orders of Mammals, see Mammals.) 



2. Birds. — All the feathered tribe. (For orders of Birds, 

 see Birds.) 



3. Batra'chia. — Animals of the frog tribe. 



4. Rep'tiles. — Such as the turtle, crocodile, serpent, lizard, 

 etc. ( For orders of Reptiles, see Eeptiles.) 



5. Fish'es, — Those adapted to breathe by means of water, so 

 as to be capable of living in that element only. (For orders 

 of Fishes, see Fishes.) 



Articiilata. — The second division is characterized by a jointed 

 or articulated covering, consisting of a series of annulations 

 or rings corresponding to the internal skeleton of the ver- 

 tebrated animals, and embraces 



1. In'sects. — Articulate animals having bodies composed of 

 three distinct parts, the head, thorax, and abdomen ; the 

 legs, six in number, with usually two or four wings at- 

 tached to the thorax ; and along the sides of the abdomen 

 minute punctures by means of which the respiration takes 

 place. 



2. Arach.'nida. — Articulate animals with legs, but without 

 wings, including spidei-s, mites, scorpions, etc. 



3. Crusta'cea. — Articulate animals adapted to breathe by 

 means of gills, and thus to I'eside in or near water, instead 

 of inhabiting the air, as crabs, lobsters, shrimps, etc. 



4. Cirrhipe'da. — The barnacle tribe, or tendril-footed animals. 



5. Myriapo'da. — Articulate land animals having many legs, 

 as the centipede. 



6. Annelida. — Articulate animals whose bodies possess no 

 jointed members, as the leech, and worm tribe. 



7. Entozo'a. — Articulate animals inhabiting the bodies of 

 other animals, as the tapeworm. 



Mollusca. — The third division includes species whose bodies 

 are soft and inarticulate. Some of them are naked, while 

 others are invested in a shell. With the exception of a 

 single family they have no distinct organ of sense, except 



