ABBREVIATIONS 



a.o., adhesive organ 



hyp., hypophysis 



hyp.p., hypophysial pit 



inf., infundibulum 



n.p.ep., vestigial epithelial lobe (parsepi- 



thelialis) 

 n.p.n., new neural lobe 

 o.p., olfactory placode 



op.v., optic vesicle 

 ot.v., otic vesicle 

 p.f., pituitary floor 



p.g., pars glandularis of the hypophysis 

 p.i., pars intermedia of the hypophysis 

 p.n., pars neuralis of the hypophysis 

 i.p.f. thickened portion of pituitary floor 

 I, II, III, branchial arches 



PLATE 1 



EXPLANATION OF FIGURES 



11 A 4-mm. frog larva (R. boylei) showing the surface characteristics at a favor- 

 able stage for epithelial hypophysectomy. (a) Ventrolateral, (b) ventrocephalic 

 view. 



12 A median sagittal section of a frog larva of approximately the same age and 

 size as shown in figure 11. 



114 



