140 



BIOLOGY OF THE LABORATORY MOUSE 



of circular smooth muscle fibers and held together in groups by a thin con- 

 nective tissue membrane (Fig. 68). The color and apparent consistency of 

 the secretions of the accessory glands in preparations stained with hema- 

 toxylin and eosin is characteristic and helpful in identifying them. The 

 tubules of the ampullary glands contain an intensely red staining, dense, 



Secretion 



Fig. 68. — Ampullary gland. (X200.) 



homogeneous secretion which has a tendency to shrink away from the 

 epithehal lining and lie free in the lumina. 



Vesicular glands. — The vesicular glands are long, narrow and curved at 

 their tips. Internally there is a large, elongated cavity with medial alveolar 

 outpocketings. The epithelial lining consists of a single layer of tall 

 columnar cells having distinct cell outlines. The large oval nuclei are near 

 the bases of the cells. The slightly basophilic cytoplasm contains dark 

 secretion granules which are surrounded by lighter staining areas (halos) 

 (Fig. 69). When the lumen is distended by secretion the epithelial cells 

 are lower and do not contain secretion granules. The mucosa, especially on 

 the side containing the alveolar outpocketings, is thrown into many fine, 

 intricate folds. The gland is surrounded by smooth muscle fibers and 



