Aristotle 31 



from the ground. For even among land-plants there are some 

 that are independent of the soil or even entirely free. Such, 

 for example, is the plant which is found on Parnassus, and 

 which some call the Epipetrum [probably Sempervivum tec- 

 tor um, the common houseleek]. This you may hang up on 

 a peg and it will yet live for a considerable time. Sometimes 

 it is a matter of doubt whether a given organism should be 

 classed with plants or with animals. The Tethya, for instance, 

 and the like, so far resemble plants as that they never live free 

 and unattached, but, on the other hand, inasmuch as they have 

 a certain flesh-like substance, they must be supposed to possess 

 some degree of sensibility.' * 



The Acalephae or Sea-nettles, ... lie outside the recognized 

 groups. Their constitution, like that of the Tethya, approxi- 

 mates them on the one side to plants, on the other side to 

 animals. For seeing that some of them can detach themselves 

 and can fasten on their food, and that they are sensible of 

 objects which come in contact with them, they must be 

 considered to have an animal nature. . . . On the other hand, 

 they are closely allied to plants, firstly by the imperfection of 

 their structures, secondly by their being able to attach them- 

 selves to the rocks, which they do with great rapidity, and 

 lastly by their having no visible residuum notwithstanding that 

 they possess a mouth.' 2 



Thus i Nature passes from lifeless objects to animals in such 

 unbroken sequence, interposing between them beings which 

 live and yet are not animals, that scarcely any difference seems 

 to exist between two neighbouring groups owing to their 

 close proximity.' 3 



Some approach to evolutionary doctrine is also foreshadowed 

 by Aristotle in his theories of the development of the individual. 



1 De partibus animalium, iv. 5 ; 68 i a 15. 



2 De partibus animaliwn, iv. 5 ; 68i a 36. 



3 De partibus animalium } iv. 5 ; 68 i a 10. 



