ORGANIC DEVELOPEMENT. 537 



parous, or ovo-viviparoiis : this is the case with the 

 Shark. 



3. Viviparous animals are those in which no egg, 

 properly so called, is completed ; but the ovum, 

 after proceeding through the oviduct, sends out 

 vessels, which form an attachment to the interior of 

 a cavity in the body of the parent, whence it draws 

 nourishment, and therefore has attained a consider- 

 able size at the time of its birth. 



4. Marsupial animals are those, which, like the 

 Kangaroo, and the Opossum, are provided with 

 abdominal pouches, into which the young, born at 

 a very early stage of developement, are received 

 and nourished with milk, secreted from glands con- 

 tained within these pouches. As the young, both in 

 this and in the last case, are nourished with milk 

 prepared by similar glands, or Mammce, the whole 

 class of viviparous and marsupial animals has re- 

 ceived, from this characteristic circumstance, the 

 name of 3Iammalia. 



Chapter II. 



ORGANIC DEVELOPEMENT. 



Although the study of organic structures in their 

 finished state must tend to inspire the most sub- 

 lime conceptions of the Great Creator of this vast 

 series of beings, extending from the obscurest plant 

 to the towering tenant of the forest, and from the 

 lowest animalcule to the stately elephant and 

 gigantic whale, there yet exists another depart- 



