292 C. JUDSON HERRICK 



Our analysis of the eminentia thalami is still incomplete. 

 So far as shown by our preparations it appears to serve as an 

 intermediary between the primordium hippocampi (the olfacto- 

 visceral palHal area) and the somatic parts of the thalamus. 

 In reptiles and mammals the nucleus anterior thalami stands 

 in somewhat similar intermediate relation between the mammil- 

 lary body and the somatic parts of the thalamus by way of 

 the mammillo-thalamic tract of Vicq d'Azyr. And the mam- 

 millary body, in turn, receives part of its afferent nerve supply 

 from the hippocampus. It may be that in the course of verte- 

 brate evolution when the direct cortico-thalamic pathway found 

 in Amphibia was interrupted its place was taken functionally 

 by the longer and more complex connection by way of the 

 column of the fornix and the mammillo-thalamic tract. 



The pedunculus cerebri and motor tegmentum 



The cell bodies of the neurons of this region are arranged in 

 the stratum griseum in somewhat more open formation than 

 are those of the overlying tectum and the stratum griseum is 

 here somewhat thinner. Their dendrites are long and they 

 branch widely throughout the stratum album, but in general 

 they are less contorted than those of the tectum (figs. 23, 24, 31, 

 32, 33). Dendritic branches are given off at the boundary 

 between the gray and white layers which run tangentially to 

 the gray layer and form dense arborizations among the tangential 

 axons of this region (fig. 32). 



Among the motor tracts of the tegmentum are occasional 

 tract neurons whose cell bodies lie in the stratum album and 

 whose dendrites spread out in the neuropil between the tegmen- 

 tal fascicles (figs. 24, 35). The dendrites of some of the most 

 ventral cells of the tegmentum are directed downward to 

 arborize in the neuropil of the interpeduncular nucleus (fig. 61). 



The stratum album of the cerebral peduncle receives the 

 following tracts: the brachium conjunctivum from the cere- 

 bellum; the tractus tegmento-interpeduncularis from the emi- 

 nentia subcerebellaris tegmenti; fibers from the tectum by way 



