490 TRANSACTIONS OF THE CANADIAN INSTITUTE. [Vou. VIII. 
it is difficult to escape the conclusion that in the free-living stage as well 
the skin must be an important factor in respiration. 
The development of gills in the first place is governed by the same 
necessity as exists in other Amphibia; sections show that the beginning 
of their degeneration coincides with the skin becoming sufficiently de- 
veloped for the circulation in it to become somewhat extensive; and 
that their diminution keeps pace with the elaboration of the cutaneous 
circulation, just as in most Amphibia it accompanies the increasing 
activity of internal gills or lungs. 
EARLY DEVELOPMENT AND DEVELOPMENT OF INTERNAL ORGANS. 
Studies in these fields have revealed several points of interest which 
it is proposed to consider in a future paper. 
