430 SANGUIFEROUS SYSTEM. 



ceeding observers. Cavolini observed in the longitudinal 

 cavity of the fleshy axis of their body, a fluid in motion, 

 containing distinct globules like those composing the flesh, 

 which continued during the whole life of the animals, to 

 ascend and descend through all the stems, and the branches 

 and the polypi. These globules, he observed, were contained 

 in a more thin transparent and colourless fluid, not at first very 

 obvious, and he saw them carried upwards and downwards, 

 and sometimes transversely in the cavity of the fleshy axis. 

 The same phenomenon, he perceived, in all the tubular va- 

 giniform keratophytes, the transparency of whose parietes 

 allowed their interior to be examined through the micros- 

 cope, and, comparing their circulation to that of the larvee 

 of insects, he designated the fleshy canals through which 

 the blood moves as the heart of these polypipherous animals. 

 The same motions, indeed, in the fleshy axis of the common 

 sertularia geniculata had been observed by Loefning, and 

 described by Pallas before the time of Cavolini. Olivi, who 

 subsequently examined the phenomena of the circulation in 

 sertularice, considered them as depending on the food and 

 water swallowed by the polypi, which were thus subjected to a 

 peristaltic motion, merely to assist in their digestion. Flem- 

 ing pointed out a similar circulation in the fleshy axis of the 

 campanularia gelatinosa. Chiaje considered the ciliated ten- 

 tacula of zoophytes as their branchial organs, and supposed 

 that their circulating blood is thus transmitted to them for 

 aeration ; he perceived also sanguiferous vessels extending 

 from the base of the polypi in the coral and gorgonia, and 

 forming a superficial reticulate plexus in the caryophylUa. 

 Nordman described a similar circulation of the blood in the 

 alcyonella diaphana. which he compared to that seen in the 

 cells of the char a ; and the motions which I have long since 

 described in the polypi of flustra, virgularice, pennatu/ce, 

 and other zoophytes, I have referred to the action of minute 

 vibratile cilia the common agents of all analogous move- 

 ments in the lowest tribes of animals, and which probably 

 continue to line the serous tubes of the sanguiferous system 

 in all the higher classes, as they are seen vibrating on the 

 serous lining of the cerebral ventricles, even in mammalia, 

 and the most complex form of the sanguiferous system in 

 the animal kingdom is but an extension of the simple cell of a 



