104 Bulletin of Laboratories of Dcnison University. [Voi. xiii 



TABLE OF THE GUSTATORY PATHS IN FISHES. 



A. Peripheral Neurones— Gustatory neurones of the first order. 



/. Radix communis facialis. 

 II. Radix cofumuiiis glossopharyngei. 

 III. Radix conmiunis vagi. 



These radices contain unspecialized splanchnic fibers in addition to 

 gustatory fibers. In their intra-medullary courses they unite to form 

 the fasciculus communis of the Ichthyopsida, or the fasciculus solitar- 

 ius of birds and mammals. In some animals the secondary gustatory 

 fibers are also in part represented in this tract. 



B. Nucleus gustus primus. 



The communis roots terminate in a medullary center which may be 

 termed the primary communis center. That portion of this center 

 which receives the gustatory component of these roots is the primary 

 gustatory nucleus. It may be single, but in the fishes described in 

 this paper is double. 

 /. Lobus Vagi. 



1. Layer of root fibers. 



2. Layer of secondary neurones. 



1) Chief secondary neurones. 



2) Intrinsic secondary neurones. 



3. Layer of secondary gustatory tracts. 



4. Layer of motor neurones. 



5. Ependyma. 



These layers occur as above only in some cyprinoids. 

 In place of the 4th layer in siluroids is the nucleus inter- 

 medins vagi, and in these fishes the chief gustatory neu- 

 rones are arranged in dorsal and lateral groups with some- 

 what different secondary connections. 

 //. Lobus facialis ( =tuberculura impar=lobus trigemini, Mayser). 



1. Chief secondary neurones. 



2. Intrinsic secondary neurones. 



3. Nucleus intermedius facialis. 

 ///. Lobus glossopharyngei \^r\. cyprinoids only). 



C. Tractus gustus secundus descendens. 



1 . Pars facialis (distinct only in cyprinoids and siluroids) . 



2. Pars vagi (part of the spinal portion of the fasciculus solitarius in 



mammals). 



D. Tractus gustus secundus ascendens (central gustatory tract = "sekun- 



dare Vagus-Trigeminusbahn," Mayser). 



1. Pars facialis (in cyprinoids and siluroids only). 



2. Pars vagi. 



E. Nucleus gustus secundus inferior. 



F. Nucleus gustus secundus superior (central gustatory nucleus = "Rin- 



denknoten," MAYSER:=secondary vagus nucleus, Johnston). 



1. Commissure of secondary gustatory nuclei. 



2. Intrinsic neurones (mainly commissural? ). 



