28O INEZ L. WHIFFLE. 



blood than those of a specimen which had meanwhile lived a free 

 aquatic life with access to the air. Apparently the skin, which, 

 being supplied with capillaries may be looked upon as an acces- 

 sory respiratory apparatus, had proved itself, in the emergency, 

 equal to the extra demand made upon it. 



An interesting effect of the disuse of lungs in this experiment 

 showed itself in the great difficulty with which specimens, thus 

 confined to the water, reestablished the habit of filling the lungs 

 with air when they were released from their imprisonment. Or- 

 dinarily, when a Diemyctylus swims to the surface and takes in 

 air by the gulping process already described, there is an abun- 

 dant visible proof of the fact that air has entered the lungs in the 

 increase in girth of the body and especially in the immediate in- 

 crease in buoyancy to such an extent that the specimen which 

 before had been able to sustain itself in the water only by active 

 swimming, suddenly becomes lighter than water and passively 

 floats. When, however, specimens which had for several days 

 been prevented from using their lungs were once more set free in 

 the water and swam to the surface, although great gulps of air 

 were taken, there was not the usual subsequent increase in buoy- 

 ancy and the air escaped immediately in large quantities from 

 both nostrils as the head sank again below the surface of the 

 water. The effort to fill the lungs was repeated many times in- 

 terspersed with intervals of rest lasting 15 or 20 minutes, so that 

 several hours elapsed before any effect seemed to be produced 

 upon the disused lungs. One could from the fruitless efforts of 

 the animals imagine the lungs in a collapsed condition, the inner 

 surfaces in contact with each other, and therefore resisting the 

 entrance of air ; and such, indeed, was found to be the case in 

 other specimens which had been similarly confined under water 

 and then killed without having had access to the air. 



B. The Hydrostatic Habits of Lunged Salamanders. 

 Having discussed the various methods of respiration of lunged 

 salamanders we are now prepared to describe those particular 

 habits which involve, as will be shown, the use of the ypsiloid 

 apparatus. Since my more extended observations have been 

 made upon Diemyctylus viridesccns, this species is the one which 



