STOMACH. 



[ 619 ] 



STOMATA. 



Fig. 708. 





Fig. 709. 



% 



(f 







Fig. 710. 





Fig. 708. Gastric gland with cylinder-epithelium, from the pylorus of a dog. a, principal cavity ; b, tubular pro- 

 cesses arising from it. Magnified 60 diameters. 



Fig. 709. Gastric gland from the middle of the stomach, a, principal cavity ; b, primary, and c, terminal branches 

 arising from it. Magnified 60 diameters. 



Fig. 710. Portions of a terminal branch, the upper representing a longitudinal, the lower a transverse section, a, 

 basement membrane ; b, large cells in close apposition with it ; c, smaller epithelial cells surrounding the cavity. 

 Magnified 350 diameters. 



pylorus ; some of them also give off a csecal 

 branch. 



The gastric glands consist of a delicate 

 basement membrane, lined in the upper 

 third with cylindrical epithelium, the lower 

 portion being filled with large, pale, poly- 

 gonal, finely granular cells, not arranged in 

 a laminated form. 



In many animals the gastric glands are of 

 more complicated structure than in man, and 

 two distinct kinds exist, in one, secreting 

 mucus, the tubes being lined with cylin- 

 drical epithelium ; whilst in the other, which 

 secretes gastric juice, rounded epithelial cells 

 occur, and the walls are expanded at intervals. 



Closed follicles resembling the solitary 

 glands of the small intestines are met with 

 in the stomach ; they are, however, incon- 

 stant and variable in number. 



The stomach is lined by cylindrical epi- 

 thelium. 



BiBL. Kolliker, MikrosJc. Anat. ii. 137, 

 and the Bibl. therein ; Todd and Bowman, 

 Phys. Anat., <^c. 



STOMATA (plural of Stoma).— This 

 name is applied to the structures which 

 constitute the passages of communication, 

 through the Epidermis of plants, from the 

 intercellular passages to the external air. 

 They occur almost exclusively on the green 

 parts of plants, and are absent from the 

 epidermis of roots, also on the surface of 

 all structures growing under water. The 

 lowest classes which present them are the 

 Liverworts and Mosses, where, however, 

 they are limited to a few kinds, and in the 

 former present a peculiar organization. In 

 the Ferns they are distributed just as in the 

 Flowering Plants, where they occur princi- 

 pally upon the leaves (fig. 711), especially 

 upon the lower face, but extend also over 

 the green shoots, the parts of the flower 



