THE PARS BtTCCALIS OF THE HYPOPHYSIS 73 



lar and intermediate components. The size 40 of this vestigial 

 gland is always considerably less than that obtaining in the 

 normal tadpole of corresponding dimensions (table 6). As would 

 be anticipated, this epithelial gland, subjected as it was to a 

 varying surgical interference, leaves a vestige which shows 

 great diversity in its position as well as in shape and size. That 

 the position which this lobe assumes is of paramount importance 

 in the influence it may exert upon the other glands and upon 

 metamorphosis, is evident from a correlation of the structural 

 changes enjoyed by the partial albino with the position which 

 the buccal fragment has assumed. In the specimens thus far 

 studied, three positions have been assumed by this fragment: 



1) In the first case, this fragment, not separable into glandular 

 and intermediate components, does not reach the caudal ex- 

 tremity of the infundibular process, nor does it touch at any 

 point the true neural lobe (figs. 27, 30). The members of this 

 group, which includes the partial albinos (p 1, p 2, p 3, p 4, 

 p 5), all displayed a pronounced albinism. It is to be noted 

 that none of these animals complete metamorphosis, though, 

 as in the other groups, their thyroid glands are not atrophic. 



2) In the second case, the fragment, not separable into glandular 

 and intermediate components, does not reach its usual caudal 

 position, but nevertheless attains a definite though small con- 

 tact with the true neural lobe. This class includes a smaller 

 number of specimens (p 7, p 9, p 10), the members of which 

 display a variable pigmentary disturbance. They complete 

 metamorphosis, though tardily, and the thyroid glands exhibit 

 a pronounced colloidal hypertrophy (colloid goiter). 3) In the 

 third case, the epithelial fragment, which is separable into inter- 

 mediate and glandular components, assumes the position typical 

 of the normal animal. One specimen only fell in this class (p 8) ; 

 it did not exhibit a pronounced pigmentary upset; it completed 

 metamorphosis and had a normal thyroid gland. A study of a 



40 The metamorphic changes in all the partial albinos, except p 1, which died 

 from infection, whose hypophyses were modeled (table 6), had ceased for some time 

 prior to the fixation of the animal. It is certain that the metamorphosis would 

 never have been completed nor even materially advanced had the specimens sur- 

 vived longer. 



