i3<5 THE PHILOSOPHY 



Animals furnifhed with deftrudlve weapons, or endowed with 

 uncommon ftrength, courage, or ingenuity, are proportionally flow- 

 er in their movements than the weaker kinds. The fame remark is 

 applicable to thofe fpecies whofe food is always at hand. Worms, 

 caterpillars, and many other infeds, in order to procure nourifli- 

 ment, are under no neceffity of taking an extenfive range. But the 

 motions of birds and fifhes are extremely rapid; becaufe, in queft of 

 food, they are obliged to pafs through large tracks, and they have 

 alfo many enemies to avoid. 



Timid animals, as the hare, the rabbit, the Guiney-pig, Sec. are 

 almoft perpetually in motion. Even when perfectly undifturbed, 

 they are reftlefs, and betray a continual anxiety of danger. They 

 run about, flop fhort, ere£l their ears, and liften. The Guiney-pig 

 frequently raifes itfelf on its hind-legs, and fnuffs all around to catch 

 • the fcent of food when hungry, or to increafe its circle of hearing 

 when afraid. 



The movements of many animals are fo extremely flow, that 

 fome of them, particularly thofe of the fliell tribes, are generally 

 fuppofed to be deftitute of the power of moving. It is a common 

 notion, that both frefh and fait water mufcles have not the loco- 

 motive faculty. But this is a vulgar error. It is almoft unnecefTary 

 to mention, that the exterior part of mufcles confifts of two fhells 

 hinged together, which the animals can open or fhut at pleafure. 

 Every perfon muft likewife have obferved, in the ftrudure of the 

 animal itfelf, a flefhy protuberance of a much redder colour, and 

 denfer confiftence, than the other parts of the body. This mufcular 

 protuberance, which confifts of two lobes, has been denominated a 

 trunks or tongue: But it is an inftrument by which the creature is 

 isnabled to perform a progrefTive, though a very flow motion ; and, 



therefore, 



