Nervous System of the JiifUsoria. 63 



for, were they vascular, the movement of a liquid would be per- 

 ceived in the larger of these filaments, on account of their con- 

 siderable diameter, and of the granular substance which they 

 inclose. If, on the other hand, many of these knots which are 

 placed near the oesophagus were to be regarded as performing 

 the function of salivary glands, this view could not be taken re- 

 specting those which send distinct filaments into other parts of 

 the body, such as the mouth of the pharynx. Besides, the in- 

 testinal glands which have been already noticed, are themselves 

 very considerable organs for the function of salivation. In tliose 

 animals in which they are placed upon the intestinal canal, as in 

 the Brachiones, they may rather be named salivary than pan- 

 creatic glands ; but when the stomach is not distinct from the 

 intestines, as in the Hydatina, they at the same time perform the 

 functions of both pancreas and salivary glands. 



Finally, there is found in the middle of the body of certain of 

 the rotatoria, small isolated knots (see PL I. figs. 8 and d,gg)i 

 which are freely suspended between the long filaments ; they are 

 very delicate and simple, and give origin to other slender fila- 

 ments, or more accurately, several of these filaments, and some- 

 times only two, unite in these bodies. These small and free 

 organs, which are always placed in the same spot, have distinct- 

 ly the form of ganglions and nerves ; and they move in a pas- 

 sive manner, with the movements of the muscles. 



The second consideration which confirmed him in the belief 

 that there were nerves in the infusoria, was the particular ar- 

 rangement of the bodies we have just been considering. These 

 large knots — those most like nervous or cerebral ganglions — are 

 found placed exactly round the oesophagus and near the mouth ; 

 and it is well known that it is precisely in this place that the well 

 determined nervous ganglions are found in other animals, and es- 

 pecially in the Entomostracea, the Mollusca, and in worms. The 

 rest of the body presents a nervous distribution, simple, and also 

 by rays intermixed with ganglions, agreeing very well with what 

 we should expect. 



The discovery of a direct communication between the me- 

 dullary knots situated on the neck, near the oesophagus, and the 

 constant red points which are commonly found in the same »i- 



