304 CLASS MAMMALIA. 



the tree, if, which is common, his tail should fasten on a 

 branch ; for a singular peculiarity of this organ is to con- 

 tract at its extremity of its own accord as soon as it is ex- 

 tended to its full length. 



These animals are very easily tamed, and caresses and 

 good treatment render them extremely affectionate. We are 

 even assured, (but it appears doubtful,) that they are capa- 

 ble of being taught to execute many domestic services. 



This subgenus is distinguished by the external characters 

 of a round head, long limbs, voluminous abdomen, and 

 long prehensile tail. 



From the structure of the monkey tribe, more especially 

 from the conformation of their limbs, we are in the habit 

 of associating with them, the ideas of petulance and ac- 

 tivity. The general length and suppleness of their mem- 

 bers, and the lightness of their bodies, naturally lead us to 

 presuppose that quickness, vivacity and address, which in 

 fact they very usually exhibit. Were we desirous to re- 

 present an animal of sluggish movements and of feeble and 

 irresolute efforts, we would depict it with short limbs, and 

 a thick body. We always seek to explain the greater or 

 less facility of action in any animal by the organization, 

 the arrangement, the relative character of its bones and 

 muscles. Should we find an animal favourably organized 

 for active exertion, yet slow and embarrassed in his mo- 

 tions, we should regard it as a lusus naturas. But in 

 science, a single new observation is often sufficient to over- 

 turn rules established to all appearance on the most solid 

 foundation, and we often find that what we had been ac- 

 customed to consider as necessary is only contingent. 

 Thus for example, the Coai'ta, or four-fingered monkey, 

 better conformed for active and vivacious motion than most 

 of the tribe, which has longer limbs, and a tail which may 

 be considered as a sort of fifth hand, moves in general with 

 extrem? slowness, and seems as it were " to drag his lazy 



