86 DAVIDSON BLACK 



ophidians no such visceral component of the trapezius complex 

 was present. 



In connection with my earlier observations on the probable 

 phylogeny of the sauropsidan cucularis (5, p. 417) it is significant 

 that a definitely developed homologue of the accessory nerve 

 and trapezius complex in which somatic and visceral elements 

 are inextricably blended, has been found in every synapsid and 

 diapsid form so far examined, while variations away from this 

 condition of development have only been encountered in reptiles 

 belonging to the more modern group Squamata. 



With regard to the ventrolateral X motor nucleus which appears 

 for the first time in phylogeny in reptiles, Kappers has suggested 

 the possibility of its representing a cardiac nucleus (32) . On the 

 other hand, it may possibly be correlated with the specialization 

 of the vasomotor swell mechanism (m. constrictor venae jugularis 

 of Bruner, 8) so characteristically developed among reptiles. 

 However, further discussion of the significance of this cell group 

 will be postponed until the homologous area of the brain stem 

 of birds has been considered in a subsequent communication. 



Motor VII-IX complex. The characteristic origin and course 

 of the motor VII root in reptiles has been discussed at length 

 by Kappers in his earlier papers (see especially 30 and 31). 

 This author has shown that the pronounced frontal genu of the 

 VII motor root in these forms is due for the most part to the 

 restraining influence of the dorsal arcuate fibers from the tuber- 

 culum acusticum and especially those from the nucleus laminaris 

 (Holmes, 27). The caudal genu of the root is the result of the 

 ventrolateral migration of the nucleus from its original dorsal 

 location. This displacement is most evident in Varanus and 

 is less marked in Damonia, Boa, Chelone and Alligator in the 

 order mentioned. 



The degree of caudal migration of the motor VII nucleus in 

 reptiles (i.e., the length of the horizontal root) has been shown 

 by Kappers to be directly correlated with the size and importance 

 of the terminal VII-IX gustatory nucleus. In chelonians the 

 tongue is supplied with taste buds over the whole of its surface 

 (Tuckerman, 37), while this organ is practically destitute of taste 



