326 Henry L. Bruner 



rostro-lateralis the tubules of the gland lie between the nasal muscles and 

 the above-mentioned process of the maxillare. At the rostral margin of 

 the maxillare the medial tubules of the gland unite to form a common 

 duct which extends forward between the skin and the constrictor 

 naris and opens on the caudo-medial portion of the nasal opening. 

 The lateral portion of the gland consists of a few tubules only, 

 which extend forward between the maxillare and the constrictor 

 naris toward the nasal opening, on whose caudo-lateral margin they 

 terminate. 



2) In Salamandva maculosa we find relations which differ from 

 those just described chiefly in the more lateral position of the 

 glandula nasalis externa, which lies for the most part in the angle 

 between the two dilatator muscles (Fig. 1, PI. XVII). In the specimens 

 examined the discharge of secretion occurred only at the caudo- 

 median angle of the nasal opening. 



From a careful consideration of the above conditions, it may 

 be safely assumed that the simple forward and backward movement 

 of the caudal lip of the nasal opening must produce a variation in 

 pressure upon the tubules of the external nasal gland. On account 

 of the relation of the gland to the constrictor naris, it is evident 

 that the pressure upon the anterior portion of the gland will reach 

 its maximum with the contraction of that muscle; the posterior part 

 of the gland, however, and particularly that portion which is covered 

 by the facial process of the maxillare, will be under maximum 

 pressure during the contraction of the two dilatator muscles. At the 

 time of opening the naris, therefore, the fluid contents of the posterior 

 part of the gland would be pushed forward. The contraction of the 

 constrictor naris, on the other hand, produces an increase of pressure 

 in the immediate neighborhood of the nasal opening, whereby the 

 secretion contained in the anterior portion of the gland will be pressed 

 out upon the margin of the nasal opening. 



3) Amblystoma tigrinum. The relation of the glandula nasalis 

 externa to the nasal muscles in this species deserves particular 

 attention. In the specimen examined the gland consisted of about 

 fifteen tubules, whose caudal portions lay between the two dilatator 

 muscles and the skin. Anteriorly, some of the lateral tubules of the 

 gland discharge under the lateral end of the constrictor naris, close 

 to the angle between the last named muscle and the dilatator naris 

 accessorius. Other tubules, however, including the majority, take a 

 direction toward the middle of the constrictor naris, through which 



