84 Bulletin of Laboratories of Dcnison University, [voi. xiii 



and lateral chief secondary gustatory neurones. Deeply embed- 

 ded in the substance of the medulla oblongata ventrally of the 

 main body of the vagal lobe is an area filled with cells some- 

 what larger than the intrinsic neurones but much smaller than 

 the chief secondary neurones, which may be termed intermedi- 



Fig. 2^ . Three intrinsic neurones of type II from the left vagal lobe of 

 Ameiurus nebulostis. From a GoLGi preparation. X 60. 



The secondary communis tract(j'.^.A)which appears to arise among these cells, 

 in reality springs from cells lying farther dorsally which are not impregnated in 

 this preparation. Superficial root fibers of the vagus are impregnated at the bor- 

 der of the vagal lobe. sp. V., spinal V tract ; V, ventricle. 



ary neurones (nucleus intermedins vagi). Their neurites enter 

 the substantia reticularis and other conduction pathways be- 

 tween the sensory and motor nuclei. Ventrally of the vagal lobe 

 and not properly to be considered a part of it is the nucleus 

 ambiguus, close to the median line in the floor of the fourth 

 ventricle. The communis roots of the IX and X nerves enter 

 the lobe at its ventrolateral border, some descending along the 

 lateral aspect of the oblongata to the region of the commissura 

 infima Halleri, forming the descending communis root of the 

 vagus, others passing directly inward under the lobe to termin- 

 ate in the lobe along its inner or \'entricular border, forming the 

 deep communis roots of the vagus and glossopharyngeus, while 



