The Lateral iSTasal Glands of Amphiiima. 149 



of the central tubules of the lobes the branches are characterized by 

 a tall columnar epithelium and, for the most part, very narrow 

 lumina. They are evidently the actively secreting portions of the 

 glands, while, judging from the large amount of coagulated material 

 in the lumina of the central tubules, the latter serve as the reservoirs 

 in which the secretion is held. 



The central tubules of the various lobes gradually come together 

 as they approach the orifice of the gland ; but, so far as I have been 

 able to determine, there is no single collecting tubule into which all 

 the others open. The number is gradually reduced, however, by 

 the confluence of the central tubules of the various lobes until a single 

 one remains to make its way to the orifice as the duct of the gland. 

 Although somewhat smaller in diameter than many portions of the 

 central tubules, this duct has a large lumen lined with a low epithe- 

 lium. 



Several of my dissections and serial sections show a small anterior 

 lobe, somewhat apart from the larger mass of the gland ; this lobe 

 connects with the duct of the glandular mass immediately posterior 

 to the point where it bends to make its way across the constrictor 

 muscle to its orifice. The method of development of the gland, to be 

 discussed later, offers a possible explanation of the existence of this 

 lobe. 



A dense layer of connective tissue invests the entire gland while 

 each lobe has a thinner investment. The gland is well supplied with 

 blood-vessels. I have been unable to determine with certainty the 

 iimervation of the gland. A large nen^e bundle, ramus glandularis 

 opthalmici profimdi II (Wilder), passes through a foramen of 

 the maxillary bone, and issues in close proximity to the gland, in fact, 

 the tubules of one lobe of the gland extend a short distance into this 

 nerve canal. Althougfi this nerve lies beside the gland throughout 

 the remaining extent of the latter, I have been unable to demonstrate 

 that any of these nerve fibers actually enter the gland. A branch of 

 this nerve does, however, go to the spiral fold, and it is possible 

 that some fibers of this branch innerve the gland also. The ana- 

 tomical association of the gland and the nerve may, at any rate, be 

 explained by the fact that the gland tubules in their development 



