10G PIGMENTARY GROWTH AFTER ABLATION OF 



9. The posterior lobe is invariably diminished in size, asym- 

 metrical in shape, and atypical in position in the albino. More- 

 over, in the albino the floor of the infundibular process — pituitary 

 floor — normally in contact with the epithelial hypophysis, does 

 not undergo the secondary thickening which takes place in the 

 normal subsequent to the juxtaposition of the epithelial hy- 

 pophysis with this structure, but retains its membranous struc- 

 ture. 



10. Attempts to remove the buccal hypophysis occasionally 

 leave a sufficiently large fragment of the epithelial hypophysis 

 in place for complete regeneration to occur. Other instances of 

 incomplete removal of the epithelial part of the gland produce 

 animals which are altered in a characteristic waj^. We have 

 termed these 'partial' albinos. As far as their appearance is 

 concerned, in most instances these animals are typical albinos 

 and the incomplete nature of the operation is only disclosed 

 later when a development of the limbs appears. Indeed, some 

 of these 'partial' albinos furnished the only instances of the 

 complete metamorphosis of albinous larvae. Our present knowl- 

 edge of the intimate relationship of the thyroid to metamor- 

 phosis would lead us to predict that the thyroid gland at least, 

 was not interfered with. As a matter of fact, anatomical study 

 of all of the 'partial' albinos showed that not only the thyroid, 

 but that all of the internal secretory glands, with one exception, 

 were undiminished in size or degree of development. Indeed, in 

 a limited number of those 'partial' albinos which completed 

 metamorphosis the thyroid was greatly hypertrophied (colloid 

 goiter) and frequently accessory thyroids were formed. 



11. The neural lobe of the 'partial' albino is usually dimin- 

 ished in size and is invariably atypical in shape and position. 



12. About the atypically placed epithelial fragment of the 

 hypophysis of the 'partial' albino there is formed a 'novel' 

 neural lobe, a structure apparently formed not only by the 

 indentation of this epithelial fragment in the brain tissue, but 

 by an actual hypertrophy of the adjacent parts. Not infre- 

 quently in these specimens there is no recognizable neural lobe 

 such :is invariably is exhibited by the typical albino. 



