THE NERVOUS STRUCTURES IN THE PALATE OF 

 THE FROG: THE PERIPHERAL NETWORKS 

 AND THE NATURE OF THEIR CELLS AND 

 FIBERS. 



By C. W. Prentiss, 



Instructor of Biology, Western Reserve University. 

 With 12 figures. 



On account of the doubts which have recently been thrown 

 upon the neurone theory by the researches of Apathy, Bethe 

 and others, especial attention has been drawn to the networks 

 of cells and fibers which apparently form an important part of 

 the peripheral nervous system in most Metazoa. 



In his recent book on the nervous system Bethe (:03) 

 discusses at some length the comparative histology and physi- 

 ology of these structures. According to his own investigations 

 and the observations of Hesse ('95), the brothers Hertwig 

 ('78), and Eimer ('79), the nervous system of the Medusae is 

 composed largely of nerve cells and fibers which are united 

 into a diffuse network. The neurofibrillae of this network form a 

 basketwork about the nuclei of the cells, and are connected 

 both with muscle-fibers and with sensory organs in the epi- 

 thelium of the sub-umbrella. Smidt ('.02) describes a sub- 

 epithelial plexus in mollusks ; both he and Bethe demonstrated 

 its connection with sensory organs, and according to the physi- 

 ological experiments of the latter it also sends motor fibers to 

 the muscles. 



Among the arthropods similar structures were first ob- 

 served by Holmgren ('95). Later Bethe ('96) described 

 peripheral networks in Crustacea, and his observations were 

 verified by Holmgren ('98) and Nusbaum and Schreiber 

 ('97). 



