270 Susanna Phelps Gage 



ing the tongue viscid. In aquatic forms such a viscid secre- 

 tion naturally would not seem of much use, at least the ap- 

 pearance of the gland in the adult seems to justify this con- 

 clusion for its tubules are more shrunken and its cells have 

 less the appearance of activity. A further comparison of this 

 gland in the different groups of amphibia seems desirable. 



BRAIN OF YOUNG LARV^. PL. I. VI, VII. 



The larvae, the brains of which are figured, were about i 

 cm. long— were only a few days from the ^^g, had lost the 

 "balancers;" the eyes were large, the pectoral limbs formed; 

 they were active and responded promptly to any jar of the 

 water. Food was found in the stomach and a thoroughly in- 

 dependent existence was established. 



The description of Plate I serves to compare the adult and 

 larval brain as seen in frontal section. A comparison of fig- 

 ures 4 and 64 shows the marked differences in external form. 

 The olfactory lobes and cerebrum together are relatively short, 

 and the cerebrum is overhung by the diencephal with the 

 habense. The united dien-and mesencephal form a more 

 marked feature of the brain ; the mesencephal still farther 

 overlaps the metencephal ; large as the infundibular region is, 

 it is almost enclosed by the cephalic extension of the lateral 

 wings of the epencephal which project far laterad also (Fig. 

 64-65). In general the argreement of the larval diemyctylus 

 with amphiuma as described by Kingsley (30) is very close. 



The cells composing the cinerea are much larger than in 

 the adult, and in many places are distinctly arranged in rows 

 radiating from the endyma (PI. VII). This arrangement exists 

 in the adult (Fig. 51) but does not show with low magnifica- 

 tion. The alba of the larva is small in quantity' relativelj' — 

 being massed at the sides — with a small amount crossing the 

 meson (Fig. 6, 67). 



Rhinencephal. — The olfactory lobes are less separated from 

 the hemicerebrums than in the adult, though the caudal limit 

 of the former may be determined by the position of the second 

 olfactory nerve root which is present. Cinerea occupies a 

 large portion of the lobes and the continuity of ectal with 

 ental cinerea is extensive. 



