280 FREDERICK TILNEY 
The post-infundibular eminence of the mammal seems to bear 
a clear homology to that of the bird and selachian. The embryo- 
logical evidence concerning the development of this region is 
strongly suggestive if not conclusive in establishing this homol- 
ogy. The same facts make it impossible to consider the post- 
infundibular eminence as phylogenetically related to the saccus 
vasculosus, and hence raise serious objection to the term 
‘eminentia saccularis’ as applied to it. 
There can be little doubt that the posterior lobe of the se- 
lachian is the homologue of the mammillary body in the bird 
and mammal. 
