Herrick, Brain of Certain Reptiles. 135 



is high up and the fibres then come into close relations with the 

 corpora posterioria. The number of cells scattered in this region 

 of interblending (niger locus) is not large but much greater 

 than at first appears by reason of the dispersness of the 

 nidulus. (Plate XVI., Fig. 7; Plate XVI., Fig. 10, niger.) 



The cephalic peduncle of the cerebellum was not definitely 

 located. A few dark fibres coming from the base of the cere- 

 bellum can be traced in a lateral arch cephalad to the region of 

 the ruber, where they seem to turn dorsad but their actual 

 course is simple surmised to correspond with that in fishes. It 

 thus appears that, if the above surmise is correct, the amphibian 

 cerebellum has the same major connections as other groups. 



The cerebellum is ventro-laterally supported by a dense 

 nidulus which Osborn figures and mentions; this "dentatum" 

 (see Plate XVII., Figs. 2-3.) contains numerous spindle 

 cells from which arise fibres constituting a tract which arches 

 cephalad and penetrates the cell-clustre lying laterad of the nid- 

 ulus posterior ("mucleus magnus"). The ultimate destination 

 of the fibres is not easy to demonstrate but they can be traced 

 to beneath the "colliculi" and apparently terminate in the 

 sensory niduli of the thalamus. 



The tract arising from the central or axis cylinder processes 

 of the cells of Purkinje pass directly caudo-lateral and form the 

 restiformia on the dorso-lateral aspects of the medulla. The 

 fibres are thick and uniform. 



The corpus posterior consists of a more or less spheroidal 

 body with a dense peripheral zone of cells whose apex process- 

 es project into the core of the organ. This is one of the num- 

 erous illustrations of a pseudo-epithelial arrangements of cells, 

 reminding one of the rodundus of fishes. In the caudal aspect 

 the cells, which have deeply staining muclei, are as closely ar- 

 ranged as possible ; elsewhere less compactly. The core is less 

 close in structure than the periphery. The middle peduncle of 

 the cerebellum comes into very close relations with it though 

 the nature of the connection is not clear. (Plate XVIIL,Fig.9.) 



While not here especially concerned with the homologies 

 of the cranial nerves we may note in passing that the three eye- 



