B. VIII.] THE HISTOET OF ANIMALS. 195 



which of these classes some marine objects belong ; for many 

 of them are attached to the rock, and perish as soon as they 

 are separated from it. The pinnae are attached to the rocks, 

 the solens cannot live after they are taken away from their 

 localities ; and, on the whole, all the testacea resemble plants, 

 if we compare them with locomotive animals. Some of them 

 appear to have no sensation ; in others it is very dull. The 

 body of some of them is naturally fleshy, as of those which are 

 called tethya ; and the acalephe and the sponge entirely re- 

 semble plants; the progress is always gradual by which one 

 appears to have more life and motion than another. 



4. In the vital actions also we may observe the same man- 

 ner. For vegetables which are produced from seed ap- 

 pear to have no other work beyond reproduction ; nor do 

 some animals appear to have any other object in their exist- 

 ence. This object then is common to them all ; but as sen- 

 sation advances, their manner of life differs in their having 

 pleasure in sexual intercourse, in their mode of parturition 

 and rearing their young. Some of them, like plants, simply 

 accomplish their peculiar mode of reproduction at an ap- 

 pointed season, and others are diligent in rearing their 

 young ; but as soon as this is accomplished they separate 

 from them, and have no farther communication ; but those 

 that are more intelligent, and possess more memory, use 

 their offspring in a more civilized manner. 



5. The work of reproduction is one part of their life, the 

 work of procuring food forms another. These two occupy 

 their labour and their life. Their food differs in the sub- 

 stances of which it consists, and all the natural increase of the 

 body is derived from food. That which is natural is pleasant, 

 and all animals follow that which is pleasant to their nature. 



CHAPTEE II. 



1. ANIMALS are divided according to the localities which 

 they inhabit ; for some animals are terrestrial, others are 

 aquatic. They also admit of a ternary division, those that 

 breathe air and those that breathe water, one of these classes 

 is terrestrial, the other is aquatic ; the third class does not 

 breathe either air or water, but they are adapted by nature 

 to receive refreshment from each of these elements ; and some 

 of these are called terrestrial, others are aquatic, though they 



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