MOVEMENTS OF ROTIFEKS. Ill 



applied to the surface, (as in nerveless creatures,) 

 or the indirect (reflex) result of such stimulants 

 in beings like the rotifers, who have a nervous 

 system; or the result of sensations^ which excite 

 actions without previously referring the matter to 

 the decision of a will. It must not, however, be 

 too readily assumed that the behaviour of creatures 

 possessing distinct organs is entirely automatic; and 

 we must not forget that even the best physiologists 

 know very little concerning tlie range of functions 

 which the nervous ganglia of the invertebrata are 

 able to discharge. 



