278 ZOOPHYTES. 



very long, and to a great extent, in the Actinia. I know not when it 

 ceases. Thus, the number of tentacula may be a very indefinite guide to 

 systematic arrangement. 



Except in the flexibility of the stem, I can discover scarcely any 

 other feature in the analogy of the Coryna glaiidulosa, to the structure of 

 the zoophytes known to us. 



The animal functions of all are extremely obscure, nay, in most of 

 them, they are utterly unknown. We have seen indications of circulation 

 among some of the hydraoid zoophytes ; but it ought to be witnessed again 

 and again, that it may be understood, as it is certain that a multitude of 

 specimens may be subjected unsuccessfully to our instruments for that 

 purpose. We cannot say as much of the pectinate race. But it is diffe- 

 rent with the ascidian genera, for their circulation, or some process in im- 

 mediate relation, plainly ensues. 



In that fluid, which, in zoophytes, may be compared to the red blood 

 of other animals, the globules are generally black, amidst a transparent 

 matter, wherever I have been able to see them. But in the Botryllus, the 

 globules are evidently yellow. 



The food of all the zoophytes, unless the Hydra or Polypus, and the 

 Actinia, is extremely obscure. These are evidently highly carnivorous, 

 and the digestive faculty is strong. Thence also come assimilation and 

 increment. They receive almost all fleshy substances, without exception, 

 and in inordinate quantities. The stomach may be distended to any ex- 

 cess, and apparently with impunity. Indeed, nearly the entire animal 

 seems to be only a stomach. 



Thus the tentacula are, doubtless, adapted for their respective func- 

 tions, by the difference of their structure. 1. They are smooth, susceptible 

 of distension, possessed of an adhesive power, and with a terminal orifice in 

 the helianthoids. 2. Ciliated, as in the ascidian zoophytes. 3. Muricate 

 in the hydraoids. 4. Pectinate in the asteroids. Perhaps all are tubular. 

 But this is not ascertained. From what we see, however, their structure 

 is adapted for conveying the substances believed the source of aliment, 

 within reach of the mouth. 



Therefore, it is chiefly by means of the tentacula, and their appurte- 



