MAMMALIA. 397 



arctic region, six hundred miles north of it, and described by 

 Dr. (now Sir John) Richardson. It is equally distinct from 

 that of South Carolina and Georgia, a territory about as far 

 distant to the south."* 



Our notice of the several orders of mammalia shall be 

 commenced with those which are lowest in the scale, and 

 gradually ascend to man, gifted as he has been with dominion 

 " over every living thing that moveth upon the earth." 



ORDER MARSUPIATA. MARSUPIAL, OR POUCHED 

 ANIMALS. 



' Deforrn'd, unfinish'd, sent before my time 

 Into this breathing world, scarce half made up." RICHARD III. 



The greater number of the mammalia are nourished prior to 

 birth, by a network of blood-vessels named the placenta.-^ 

 This is altogether wanting in the group now under considera- 

 tion. While others do not come into the world until they 

 are provided with all their organs, these are brought forth in 

 an extremely imperfect state. The female in most instances 

 is furnished with a peculiar pouch (Latin marsiipium, a purse 

 or bag), whence the scientific name for the order. In this 

 pouch the immature young are received and nourished, and to 

 it they afterwards retreat on the approach of danger. Certain 

 bony projections, termed the Marsupial bones, are found in 

 both sexes, even in those species in which the characteristic 

 pouch does not exist. 



" The order Marsupiata," says Mr. Waterhouse, "embraces 

 a large assemblage of quadrupeds, amongst which are those 

 animals familiarly known as Opossums and Kangaroos. At 



* Travels in North America, vol. i. p. 172. The extract is given in 

 Berghaiis and Johnston's Physical Atlas, from which all our information 

 on the numbers and distribution of species is derived. 



f The mammalia which are thus nourished are termed placental; the 

 others the non-placental. Some naturalists regard this distinction of so 

 great importance, that they consider the two divisions should rank as dis- 

 tinct classes. 



VOL. II. I 2 



