ON POLYPS. 43 



streams of water forced by the contractions of the animal through 

 the orifices at the extremities of the tentacula. 



The Abbe Dicquemare* relates several curious experiments on 

 the multiplication of these animals by mechanical division. When 

 transversely divided, the upper portion still stretched out its ten- 

 tacles in search of food, which, when seized, sometimes passed 

 through its mutilated body, but was occasionally retained and di- 

 gested. In about two months tentacles grew from the cut ex- 

 tremity of the other portion, which soon afterwards began to seize 

 prey. By similar sections he even succeeded in making an animal 

 with a mouth at each end. 



(60.) The entire organization of the Actinia is evidently very supe- 

 rior to that of any animals which have been described in the preceding 

 pages ; the muscular fasciculi, now for the first time distinctly recog- 

 nisable, give an energy to their contractions very different from the 

 languid movements of the gelatinous polyps. The Actinia can in- 

 deed hardly be classed in the acrite division of the animal kingdom ; 

 the developement of muscular fibre which it presents, presupposes 

 the existence of nervous filaments, and we might a priori infer 

 their existence. Spix, many years ago, described a nervous sys- 

 tem, which he believed he had discovered, in the neighbourhood 

 of the base, or sucking disc by which the animal attaches itself to 

 foreign bodies ; in which situation he was led to look for it, by ob- 

 serving that when galvanic shocks were sent through the body, 

 convulsive movements were excited most distinctly in this part, 

 and also from the supposition that the organ of attachment, here 

 placed, must necessarily be the most abundantly endued with sen- 

 sibility, j* 



Having raised the longitudinal muscles by a slight incision near the 

 middle of the base or disc of attachment, he thought he perceived an 

 interlacement formed by some pairs of nodules, disposed around the 

 centre, which communicated by several cylindrical threads ; from 

 each nodule two filaments ran forwards, one accompanying the lon- 

 gitudinal fleshy fasciculi, the other penetrating to the internal 

 longitudinal septa, which have likewise a muscular character. Suc- 

 ceeding anatomists have, however, totally failed in their endeavours 

 to detect the arrangement here described ; and which indeed, did it 

 exist, would be contrary to every analogy with which we are ac- 

 quainted. It is more probable that the nervous system consists in 



* Philosophical Transactions, 1773. 



t Spix (Jean) Annales du Museum, tome 13. 



