322 ORDER V. INFUSORIA. 



TUBULARIA, CORALLINA, SERTULARIA, PENNATULA, and 

 HYDRA. 



Zoophytes are so contracted in their powers, and so de- 

 fective in their formation, that some naturalists have con- 

 fessed themselves at a loss whether to consider them as a 

 superior rank of vegetables, or as the humblest order of 

 animated nature. Indeed, in some of them, the marks of 

 the animal are so few, that it is difficult to fix with preci- 

 sion their place in nature ; or to tell whether it be an ani. 

 mal or a plant that is the object of our consideration. 

 However, zoophytes enjoy one faculty of which vegetables 

 are wholly deficient ; which is, either the actual ability or 

 the awkward attempt of self-preservation, by receding 

 from external contact. Though some plants may seem to 

 possess this important quality, it seems at best in them but 

 a mechanical impulse ; they are neither capable of search- 

 ing for food in the manner of animals, nor of warding off 

 the slightest danger which menaces them. 



The hydra, or fresh-water polypus, may serve to furnish 

 an example of zoophytes. At first it was conceived to be 

 a mere plant ; but was soon discovered to be a sensitive 

 ambulant, and yet to be capable of propagation by slips 

 and cuttings. There are various species of this genus ; 

 found in different situations, in ditches of stagnant water, 

 and among duck-weed : but they all possess the property 

 of re-production, in whatever form they are divided. If 

 cut into three parts, the middle puts out a head from one 

 end and a tail from the other ; and it becomes three dis- 

 tinct animals, all living like their original, and performing 

 the various offices of their species. 



ORDER V. INFUSORIA. 



INFUSORIA, or animalcules, consist of very small simple 

 animals, forming the subsequent fifteen genera; BRACHIO- 



NUS, VORTICELLA, TRIC1IODA, CERCARIA, LEUCOPERA, 



