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SCIENCE PROGRESS 



and ependyma cells. Closely applied to the ventral and 

 postero-ventral faces of this lobe is a layer of lightly staining 

 cells, constituting the pars infundibularis (P.I.) . The pars dis- 

 talis (P.D.) is a solid mass of cells detached from the pars 

 infundibularis from which it is separated by a layer of con- 

 nective tissue. The cells of the pars distalis are of two types, 

 chromophilic and chromophobic, and numerous blood-vessels 

 are scattered amongst them. 



The paired " tongue-like processes " described above in 



Fig. 3. 



Triton are present also in Rana as detached masses of cells 

 lying in very close contact with the brain floor, which, however, 

 retain a connection with the main body of the pars buccalis 

 in late tadpoles. These probably represent the pars tuberalis. 



The dorsal (saccular) surface of the infundibular process in 

 Amphibia is thin-walled and richly vascularised, but does not 

 form a definite saccus vasculosus. 



The primordium of the pars buccalis in Amphibia is solid. 



Reptilia. — Baumgartner (2) has given a very full account 



