477 



CHAPTER IX. 



MAMMALIA. 



1 . Mammalia in general. 



THE singular animals, so remarkable for their 

 anomalous shapes, their torpid vitality, and their 

 amphibious constitution, which have lately oc- 

 cupied our attention, appear placed by nature 

 as forms of transition, in the passage from those 

 vertebrated animals which dwell in the water, 

 to those which inhabit the land. The class 

 of Mammifera, or Mammalia, comprehends all 

 the animals which possess a spinal column, 

 breathe air by means of lungs, and are also 

 warm blooded, and viviparous, conditions which 

 render it necessary that they should possess 

 organs, called mamma, endowed with the power 

 of preparing milk for the nourishment of their 

 young ; a peculiarity from which the name of 

 the class is derived. But they are not exclu- 

 sively land animals ; for among the mammalia 

 must be ranked several amphibious and aquatic 

 tribes, such as the seal, the walrus, the porpus, 



