An Analysis of the Juxta-Neural Epithelial Portion etc. 285 



gland is still juxta-neural in position for the main portion of its ex- 

 tent, tlie tuberai processes have alreadj^ begun to assume closer 

 relations to the saccular eminence of the tuber cinereum. The pars 

 infundibularis is now in contact with the ventral surface of the pro- 

 cessus infundibuli and infundibulum. Of the pars neuralis, the saccular 

 eminence, the infundibulum and infundibular process are all present. 

 The recessus tuberis is in communication with the recessus processi 

 infundibuli through a long infundibular recess. 



Chick of 16 days; no. H 76 (plate XV, fig. 25). The adult con- 

 ditions have been practically attained in this stage. The tuberai 

 processes [30] have been fused across the median line, and displaced 

 the pars distalis [14] ventrad out of its original juxta-neural position. 

 The fused body thus formed constitutes the pars tuberalis and has 

 assumed its ultimate juxta-neural relations. The pars infundibularis 

 has changed but little in character and relations from the conditions 

 of the next earlier stage; it is incompletely separated from the pars 

 distalis by a much reduced residual lumen. The cavity of the in- 

 fundibular process has become considerably modified in that it pre- 

 sents the branching appearance characteristic of the adult. The 

 eminentia saccularis and the recessus tuberis are clearly defined; the 

 infundibular process is connected with the saccular eminence by an 

 elongated infundibulum. 



In plate XIX the development of the pars tuberalis is shown in 

 transverse section as it appears in several stages of the cat and 

 common fowl. 



Summary and Conclusions. 



1. In all of the animals examined the neural portion of the 

 hypophysis presents three elements; i. e. [1] the eminentia saccularis 

 of the tuber cinereum, [2] the infundibulum and [3] the infundibular 

 process. The epithelial or glandular portion of the organ comprises 

 two elements; i. e. [1] the juxta-neural portion and [2] the distal 

 portion. The juxta-neural portion presents two subdivisions, the pars 

 tuberalis and the pars infundibularis. An analysis of all of the eie- 



