104 IV. 5- 



fact virtually plants and nothing more. For 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 

 classes owing to their close proximity.^^ 



A sponge ^^ then, as already said, in these respects completely 

 resembles a plant, that throughout its life it is attached to a 

 rock, and that when separated from this it dies. Slightly different 

 from the Sponges are the so-called Holothuriae and the Sea- 

 lungs,^ as also sundry other sea-animals that resemble them. 

 For these are free and unattached. Yet have they no feeling,^ 

 and their life is simply that of a*plant, separated from the ground. 

 For even among land-plants there are some that are independent 

 of the soil, and that spring up and grow, either parasitically upon 

 other plants,-"*^ or even entirely free. Such for example is the 

 plant which is found on Parnassus, and which some call the 

 Epipetrum.-''^ This you may take up and hang from the rafters, 

 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 Ascidians, 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.^^ 



In the Ascidians there are two orifices and a single septum, 

 which latter separates the part into which the animal takes the 

 fluid that ministers to its nutrition from the part by which it 

 again discharges the superfluity of moisture. For it appears 

 to have no distinct residual matter, such as have the other 

 Testacea. This is itself a very strong justification for con- 

 sidering an Ascidian, and any thing else there may be among 

 animals that resembles it, to be of a vegetable character ; for 

 plants also never have any residuum.^" Finally there runs across 

 tht middle of the body of these Ascidians a thin partition, and 

 here it is that we may reasonably suppose the part on which 

 life depends to be situated. 



The animals which some call Sea-nettles and others Acalephae ^^ 



are not Testacea at all nor included in their divisions. Their 



constitution approximates them on the one side to plants, on 



the other to animals. For seeing that some of them can detach 



681b. 



