348 E. R. HOSKINS 



the periphery of the gland there are light spots due to the fixa- 

 tion. Most of the nuclei lie parallel with the long axis of the 

 tubule, although a few are at right angles to it. The nuclei 

 always contain one very definite, and sometimes two or three, 

 nucleoli. Many of the tubules are cut transversely near the 

 central lumen (fig. 12) because they extend longitudinally for a 

 distance. Smooth muscle nuclei are present in the connective 

 tissue surrounding the tubules. The lining epithelium is strati- 

 fied, composed of two to five layers of cells, the surface layer 

 of which is squamous in some places, but in others resembles the 

 surface layer of the transitional epithelium of the mammals. 

 In this inner layer of epithelium are occasional goblet cells, 

 most of which give the customary blue colored mucous reaction 

 to Mallory's connective tissue stain, although some of them are 

 filled with granules which are colored red with this stain. 



Toward the proximal portion of the digitiform gland, as has 

 been noted before (see c Introduction'), the connective tissue 

 increases. in relative amount as compared with the parenchyma. 

 The capsule is thickened by an increase in the smooth muscle 

 which is very definitely arranged near the duct into an inner 

 circular and outer longitudinal layer. The main central lumen 

 gradually approaches the ventral surface. The number of mucous 

 goblet cells increases in the inner epithelial layer and some are 

 found also in the primary tubules. 



The duct of the digitiform gland has the same layers and 

 histological structure as the intestine, with the possible excep- 

 tion of more numerous goblet cells in the epithelium. These 

 cells are so closely packed together in places that they are 

 pushed out of their natural shape and position and give the 

 appearance of being arranged in more than one layer. Near the 

 junction of the duct and digitifozin gland the former is composed 

 of epithelium containing goblet cells on one side and glandular 

 epithelium on the other. At the junction of the duct with the 

 intestine the outer layers of the two become continuous, but the 

 epithelial duct continues anteriorly, running in the submucosa 

 of the gut, sometimes for nearly 2 cm., before it fuses with the 

 epithelium of the gut, and the lumina of the two become con- 



