NASO-LABIAL GROOVE OF LUNGLESS SALAMANDERS. 21 



tints demonstrated witJi absolute certainly the capillary action of the 

 groove and at the same time showed that//^' relation of the groove 

 to the fold renders it impossible for the naris to become flooded 

 through this capillary action of the groove even when the lower 

 end of the latter is in the water, a common occurrence under 

 normal conditions. 



Experiment +. - - The head of the specimen was thoroughly 

 dried with absorbent paper and, when normal respiration through 

 the open nares was in progress, a thin film of olive oil in which 

 lamp black was suspended was quickly spread over the whole 

 surface of the head. There was the customary opening of the 

 naris by the withdrawal of the crescentic fold, but this u>as un- 

 accompanied by the usual receding of the fluid from the edge of the 

 naris and the draining off of the naris through the groove. The 

 groove seemed wholly obliterated by the oil, which formed a 

 continuous film over it. A line of lamp black could, however, 

 be seen slowly settling to the bottom of the groove, showing 

 that the oil had entered it. The oil extended to the very edge 

 of the nasal orifice and with each often repeated closure of the 

 naris the nasal depression could be seen to fill again with the oil. 

 The animal made frequent efforts to rub off the oil and finally 

 being unsuccessful in freeing the nares of the oil it slightly opened 

 its mouth and attempted to resume bucco-pharyngeal respiration 

 through this new channel. Upon examining the interior of the 

 mouth I could see that the black oil had passed through the 

 posterior nares and had entered the mouth. 



This experiment showed that the condition of the skin border- 

 ing the naris and groove, although such as to slightly repel 

 water, did not have this effect upon the oil which could not, 

 therefore, be drained from the naris but overflowed its edges and 

 entered the nasal passages.' This indicates that t/ie secretion of 

 the naso-labial glands mixes witli oil but repels water and that it is 

 essential to the successful performance of the function of the groove. 



Experiment 5. - - In this experiment a drop of water in which 

 carmine was suspended was placed upon the naris. The par- 

 ticles of carmine were evidently too large for the groove, since 

 there was no filling of the groove by the fluid. After a moment, 

 however, there was a sudden disappearance of the larger part of 



