D. THE STOMACH, BY E. KLEIN. 555 



The surface of the mucous membrane exhibits a large num- 

 ber of capitate elevations, at the rounded apices of which the 

 orifices of the gland sacs are perceptible. It further presents, 

 in passing from above downwards, a continually increasing 

 number of microscopic villi, minute folds or processes, which 

 nevertheless are only the optical expression of the free termi- 

 nations of the septa between two adjoining inflections of the 

 mucous membrane, or rather of two adjoining short tubes, 

 opening in immediate proximity with one another. 



Bergmann* has described three types of glands : a. The well- 

 known saccular glands, presenting a large central cavity, lined 

 with cylindrical epithelium, which receives the orifices of all 

 the smaller tubes lined with gland cells ; 6. A second type, 

 found in the starling, sparrow, yellow-hammer, and crow, in 

 strix flammea and colymbus, in which the several tubes open^ 

 by means of secondary ducts, into the principal excretory 

 duct, which last may consequently be very short; lastly, 

 c. He constructs a third type of those in which all the several 

 tubes do not open by a common canal into the gastric cavity, 

 but where a number of excretory ducts open in close proximity 

 with one another, and the secretion of which is thus dis- 

 charged into that cavity. (Cypselus apus.) 



Between the extremities of the gland-sacs and the muscular 

 layer a sparing quantity of loose submucous tissue intervenes, 

 which, on the one hand, is continuous externally with the 

 septa of the muscular fasciculi, and on the other supports the 

 vessels, accompanied by which its cords penetrate between the 

 several groups of glands, partly separating their walls, and 

 partly extending into the mucosa. Amongst these fasciculi of 

 connective tissue run, not only vessels which coil around and 

 penetrate between the individual tubes, but also smooth mus- 

 cular fibres. 



In the inferior half of the glandular stomach the simple 

 tubular glands increase in number and size towards the inter- 

 mediate portion lying between this and the gizzard, in propor- 



t C. Bergmann, Einiges iiber den Driisenmagen der Vogel, "A few 

 Remarks on the Glandular Stomach of the Bird ;" Reichert and Du Bois 

 Reymond's Archiv, 1862, p. 581, fig. c. 



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