THE PARS BUCCAL1S OF THE HYPOPHYSIS 77 



greater number of 'partial' albinos, it is anticipated, will reveal 

 an overlapping of these classes, but because of the apparent 

 association between the progress of metamorphosis, the reaction 

 of the thyroid gland and the position of this epithelial fragment, 

 such a tentative classification appears justifiable and will be 

 discussed further when the thyroid glands of these specimens 

 are more specifically considered. 



The description of the picture presented by the epithelial 

 hypophysis of the partial albino would be incomplete unless we 

 added a word in regard to the structural characteristic of this 

 vestige. Its structure (in the first and second classes mentioned 

 above) is characteristic neither of the glandular nor the inter- 

 mediate components of the pituitary. Certain portions are 

 composed of acidophilic cells, other portions of cells similar to 

 those normally found in the pars intermedia. The organization 

 of those cells, however, is typical of the pars intermedia, since 

 the component cells are neither arranged in definite cords nor 

 separated by numerous nor large sinusoids (fig. 30). 



The response of the neural lobe to partial hypophysectomy 

 is of even greater value in analyzing the interrelationship exist- 

 ing between the neural and epithelial components of the pituitary 

 than was the reaction of this lobe to the complete loss of the 

 buccal component, as obtains in the albino. In size it is usually 

 diminished as compared to the normal animal of corresponding 

 dimensions and stage of advancement (table 6) and at times the 

 lobe as such is not even recognizable (specimens p 2, p 4). 

 When present it is asymmetrical in shape and position and fre- 

 quently encroaches upon the pituitary floor. Of great interest 

 are the conditions obtaining immediately about the epithelial 

 fragment. About this fragment there is formed a thickening 

 of the neural tissue which we might designate as a 'novel' neural 

 lobe. This partially surrounds and grasps the buccal fragment 

 (fig. 30), an appearance which in part may be explained by the 

 indentation which this lobe makes in the brain substance. When 

 the usual neural lobe is absent or greatly diminished in size 

 (specimens p 2, p 4), there is evident in those specimens that 

 have been thus far examined a thickening of the pituitary floor 



