The finer Anatomy of the Xervous System of Myxine glutinosa. 393 



Elasmobranches, Ganoidei and Teleostei it should be differentiated 

 into an independent nerve. This nerve contains motor elements, but 

 also elements which do not produce distinct movements when ir- 

 ritated. 



Stieda (44) considers the Glossopharyngeus of the authors to 

 be a third root of the Vagus. 



Mayser (26) states that, bet\yeen the eighth and tenth nerves in 

 the Cyprinoids, there are three nerves, — one sensible, consisting of 

 fine fibres, — one motor, thick-fibred and one sensory, running caudally 

 from the Tuberculeum acustieum, identified with the Nervus lateralis. 

 Like the spinal nerves, the two first join each other before the Vagus 

 and according to its position may be considered homologous to the 

 Glossopharyngeus. 



Hallek states that the Nervus lateralis derives its fibres from 

 the Acustico-trigemino region, but in what manner they spring he 

 was not able to ascertain. He considers the Lateralis to be a nerve 

 entirely independent of the Vagus. Allis (3) finds that in Amia 

 calva »as the root of the Glossopharyngeus issues from under the 

 root of the Nervus lateralis it receives from that root the root of the 

 so-called dorsal branch of the Glossopharyngeus. As the two roots 

 pass outwards between the two terminal branches of the Kamus 

 posterior acustici there is an apparent interchange of fibres the nature 

 of which could not be satisfactorily determined«. 



In Myxine the Nervus lateralis-glossopharyngeus leaves the 

 Medulla oblongata somewhat rostrally to the Vagus and somewhat 

 ventral to a horizontal plan laid through the central canal. It con- 

 tains both sensory and motor fibres, has a relatively considerable 

 dimension in dorso-ventral direction, but is laterally very flattened 

 and runs caudally closely pressed to the surface of the brain (Fig. 23) 

 until it reaches the Vagus root. Here it continues farther caudally 

 but is situated exteriorly to the Vagus nerves and is together with 

 these imbedded in a capsule of connective tissue. In transverse 

 section the nerve has here a meniscus form and has nearly the same 

 dimension in dorso-ventral direction as all the Vagus nerves together 

 (Fig. 22). 



The sensory fibres of the Nervus lateralis-glossopharyngeus have 

 two-fold origin; part of them run in straight rostral direction along 

 the lateral surface of the brain towards the acustic region, where 

 they vanish amongst the gray matter; the other portion turn half 

 medially and seem to end in a nucleus of gray matter situated later- 



