GO 



NATURAL HISTORY. 



191. T. What is there peculiar in the 



P. There does not appear to be any 

 mouth, viscera, or nervous system. 



Fiff. 30. * 



192. T. Give me an example of an 

 infusorial animal. 



P. The Volvox globator, which revolves 



on its axis, and contains several small 

 y lobes, each of which, it is thought, con- 

 tains a numerous emhryo race. Wh-n the 

 Volvox arrives at maturity it biusts, and the 

 globe escapes to perform like offices. 



GENERAL QUESTIONS ON LESSON XIV. 



1. Name the second and third classes of 

 Radiata. 



2. Name the fourth and fifth classes. 



3. Give examples from each class. 



4. Why have the classes been arranged 

 thus ? 



5. What is an infusorial animal? 



6. Into how many orders are the infu- 

 soria divided ? 



7. Give me an example of an infusorial 

 animal. 



RETROSPECT AND REMARKS. 



MAN, like the other animals, is subject to the law of death, but after his soul has left 

 its earthly habitation, it shall continue to exist for ever. Some naturalists have 

 excluded him from their system, because he is too exalted in the scale of creation to 

 be classed with the "beasts that perish." Among these, Aristotle, Hay, Willoughby, 

 Swainson, and others, maintain that he should not be classed with animals, but hold a 

 distinct position. Let us see why he has been classed with animals. It is argued that 

 as he is suckled at the breast of his mother, he naturally belongs to the mammalia ; he 

 is placed among unguiculated animals, because he has nails upon his fingers and toes ; 

 and is classed with the apes because some of them have a hyoid bone, (a bone situated 

 between the root of the tongue and larynx, or windpipe). Respecting this, Swainson 

 judiciously remarks " What can be a greater violation of nature all other considera- 

 tions apart than to place a solitary species of creature walking erect upon two limbs, 

 among others which walk upon four ? " 



The various systems that have been put forth by naturalists from time to time, only 

 tend to mislead the beginner; he gets within a labyrinth of them, where each is 

 striving to prove how superior it is to all others. It is on this account that GRAND- 

 iviiiKK \VIHTI:UEAD recommends his pupils to follow the system of Cuvier, until 

 sufficiently grounded in Natural History, and then to lead the others, at the same time 

 making such observations as they may think necessary in a note-book. 



M. Lamark errs in his system, by placing all animals with an internal skeleton in 

 one division, and those with an external skeleton in the other division ; because by such 

 an arrangement, animals with the rudiments of an internal vertebrae will be classed with 

 apes, lions, and other quadrupeds. As we have already remarked, Cuvier divides the 

 animal kingdom into four great divisions, and bases his classification upon the organi- 

 sation and nature of the animals themselves. It is true that there are objections to the 



* Fig. 30. The Volvox globltor, exhibiting the minute hair-like cilia, and the small globes inside, 

 with the voung escaping. 



