NASO-LABIAL GROOVE OF LUNGLESS SALAMANDERS. 9 



here an unmistakable interval between the two glandular 

 masses. 



The other region in which one of the naso-labial glands may 

 become closely related in position to other glands is in the lower 

 part of the orbit where there is a large glandular mass which 

 opens by several orifices on the inner surface of the lower lid. 

 These glands I shall speak of collectively as the orbital glands. 

 The tubules of these glands, following the same principles of 

 growth along lines of least resistance as do the naso-labial 

 glands, push their way around both the anterior and the posterior 

 angles of the orbit. The anterior orbital glands and the ultimate 

 branches of the most dorsal naso-labial gland may, therefore, lie 

 side by side within the orbit behind the eyeball. In no case, 

 however, has any trace of coalescence been observed ; the tubules 

 of each gland end blindly. Here, again, the condition in the 

 small adults substantiates the conclusion that the association of 

 the glands is merely one of proximity, since in the young adults 

 the naso-labial gland has not reached the orbit and therefore its 

 tubules do not even lie beside those of the orbital gland. 



This peculiar relation of the naso-labial to other glands has, 

 therefore, in all probability no significance whatever beyond the 

 fact that it is the tendency of all these glands to work their way 

 "into whatever crevice happens to lie in their course. Thus cer- 

 tain of the lateral tubules of the naso-labial glands (Fig. 5, nliii) 

 usually find out the foramen in the maxillary bone for the exter- 

 nal nasal branch of the ophthalmic nerve and enter it ; and the 

 same tendency is shown also by the intermaxillary gland, some of 

 the tubules of which escape from the intermaxillary space through 

 the anterior fontanelle and extend anteriorly immediately beneath 

 the skin of the snout, while other tubules of the same gland 

 escape through the nerve foramen which leads back into the pos- 

 terior part of the nasal capsule, and thus creep into the cavity 

 under the nasal epithelium in which the internal nasal glands are 

 located. 



So far as can be seen externally the naso-labial groove in 

 other species does not differ essentially from that of Desmogna- 

 tluts f n sea. The relation to the external naris is always the 

 same, but the method of termination at the edge of the lip varies 



