NASO-LABIAL GROOVE OF LUNGLESS SALAMANDERS. 23 



with water. These regions, on the other hand, are in the im- 

 mediate vicinity of the orifices of the naso-labial glands. The 

 motions of the crescentic fold are observable not only in opening 

 and closing the naris, but to a lesser degree as frequent slight 

 fluctuations. Undoubtedly these not only stimulate the flow of 

 the secretions of the two large glands associated with the naris 

 [cf. Bruner ('01)], but also effect the spreading of the secretion 

 around the margin of the orifice. Furthermore, the orifices of 

 the glands which are associated with the groove are elevated 

 above the groove by their location upon papillae. Thus while 

 their secretion is discharged along the edge of the groove, the 

 groove itself is kept wholly free from it. This is a necessary pro- 

 vision since because of the power of the secretion to repel water, 

 it would, if it entered the groove itself, destroy its capillary power 

 to remove water from the nasal depression. The nature of the 

 secretion is probably such that it spreads easily upon the surface 

 of the skin and thus effects the repulsion of water from the mar- 







gin of the naris and groove. This function of the secretion is 

 very important in two ways, first, it serves as a means of pre- 

 venting the frequent flooding of the nasal depression from contact 

 with drops of dew, for example ; and, second, after the flooding 

 of the naris has occurred, it acts as a means for quickly shutting 

 off the water which lodges in the nasal depression and groove 

 from the film of water upon the surrounding surface of the skin 

 and thus makes it possible for the groove to remove the residue 

 of water from the nasal depression. The large size of these 

 glands proves that their function is one of great importance. 



As to the purpose of so delicately adjusted and efficient a 

 mechanism for quickly freeing the nares from water, one can only 

 conjecture. It is undoubtedly connected with the apparently 

 universal habit among the Plethodontida and DesnwgnatJii'lce of 

 maintaining a dry condition of the nasal passages. That the ability 

 to reestablish aerial respiration so promptly is primarily because 

 of the importance for that particular mode of respiration seems, 

 however, to be disproved by the experiment above cited in which 

 specimens lived for many days immersed in water with no access 

 to air. Neither was it found in any way injurious to artificially 

 fill both the nasal passage and the whole mouth cavity with 



