ANATOMY OF THE PITUITARY BODY 



mammals, the residual lumen of Rathke's pouch can usually 

 be recognized as a space separating at least part of the pars 

 intermedia from the pars glandularis. Often the space is filled 

 with an eosin-staining, homogeneous material resembling 

 histologically — but not otherwise — ^the colloid of the thyroid. 



1. Lamprey 



2. Frog 



3. Tortoise 



4. Fowl 



7. Ox 



5. Cat 



8. Rat 



9. Man 



Fig. j. — Diagrams of the pituitary region in some vertebrates (modified from 

 Atwell, De Beer, and Tilney). Sagittal sections with the nasal end to the left. 

 Pars neuralis, stippled; pars glandularis, horizontal lines; pars intermedia, black; 

 pars tuberalis, vertical lines. No. i. The "Uebergangsteil" of the lamprey may or 

 may not be homologous with the pars tuberalis of other vertebrates (De Beer). 

 No. 4. De Beer, not confirming Tilney, denied that the fowl possesses a pars inter- 

 media. No. 7. In the ox (and pig) a cone of pars glandularis tissue, attached to 

 the pars intermedia, projects into the residual lumen of Rathke's pouch (cone of 

 Wulzen). 



In adult human beings the residual lumen often is not present 

 and the pars intermedia may be identified only with difficul- 

 ty. It is clear from the diagrams that complete hypophysec- 

 tomy may be very difficult or almost impossible in animals 

 like the rat, in which the pars tuberalis extends a considerable 



[5] 



