78 bulletin: museum of comparative zoology. 



In no case observed did there occur more than one group of such 

 ganglion cells upon the several roots of the same vagus nerve. No 

 such ganglia were found upon IX. The size of these cells shows them 

 to be of the cerebro-spinal rather than the sympathetic kind. This 

 fact is brought out by comparing them with cells of the geniculate 

 ganglion, and also wath those of the spinal ganglion, and contrasting 

 these with the sympathetic cells found at the base of the palatine. 



Embryological studies by various investigators have demonstrated 

 for both reptiles and mammals transitory root ganglia in this region. 

 These are generally interpreted as the remnants of the lost dorsal 

 roots between the first spinal ganglion and the vagus. Van Wijhe 

 ('86) and Chiarugi ('89) considered these ganglia as contributing 

 permanently to the accessorius part of the vagus. Fiirbringer ('97, 

 p. 502) recognizes the existence of these ganglia in Sauropsida, but 

 states that they later disappear entirely and have nothing to do with 

 the vago-accessorius. In mammals such rudimentary ganglia have 

 been noted in the embryo of the pig (Lewis, :03) and in man (Streeter, 

 :04). In the Amphibia IX, X, and sometimes VII, possess cutane- 

 ous components. In mammals these are reduced to a small bundle, 

 which proceeds from the jugular ganglion as the ramus auricularis, 

 and small clumps of cells may remain among the vagus roots even in 

 the adult, an indication of the more extensive existence of this cuta- 

 neous component. 



In Anolis no cutaneous fibers v/ere discovered in any of the nerves 

 between V and the third spinal; unless these rudimentary vagus 

 ganglia be ascribed to the cutaneous components, all traces of these 

 -components have been lost in these segments. In the whole group 

 of reptiles this absence of cutaneous rami appears to prevail, as no 

 mention of such nerves is made by any author. If this is the case, 

 the reptiles stand alone in the extent to which this component has 

 been lost. The birds, however, need investigation on this as well as 

 on other points. Cords (:04) has described in birds a cutaneous 

 sensory branch of VII going to the lining of the external auditory 

 meatus, to which she gave the name "ramus auricularis," the same 

 term that is applied to a nerve of similar component character in 

 mammals, but derived from X. If microscopic study should verify 

 Cords's observation, we should have in birds the persistence in VII 

 of a component which is absent from this nerve in practically all 

 other forms above fishes; but the same component would in birds 

 be absent from a nerve (X) which possesses it in all vertebrates 

 except the Sauropsida. It is important in this connection to note 



