436 



ANATOMY OF VERTEBRATES. 



334 



Longitudinal section of the 

 pylorus, cxlvih". 



ib. p. This membrane is usually of a pale pink colour, deeper 

 tinted at the pyloric than at the cardiac portion, and produced 

 into numerous wrinkled folds or ' ruga?,' which 

 are not so soon effaced, under distension, as in 

 the quadrumanous stomach. The ' basal ' part 

 of the membrane is areolar or cellular tissue, 

 connecting it to the muscular coat; it also 

 supports the vessels and nerves, forms the 

 cylinders of the gastric tubules, and is covered 

 by a delicate epithelial layer of the columnar 

 kind. The gastric tubules, fig. 337, are cylin- 

 ders of the basal membrane, packed vertically 

 side by side, and filled by cells : their inserted 

 end, d, is closed : they expand slightly before reaching the free 

 surface of the membrane, where their margins become continuous 

 with each other, so as to form a series of low ridges, the height and 

 width of which vary somewhat in different parts of the stomach. 

 The length of these tubes is about T ^-th of an inch at the middle of 

 the organ, almost double that length at the pyloric portion, and 

 half that length at the cardiac region, — a difference causing the 

 different thickness of the mucous membrane in these parts of the 

 cavity. Their diameter is about ?J~^tii of an inch, and is a little 

 increased in the pyloric ones : in some of these, blind processes are 

 continued from the inserted end ; as commonly seen in the Dog, 

 fig. 349. Toward the outlet the tubule is occupied by ' columnar 



epithelial cells,' fig. 337, c : 

 the deeper portion is filled by 

 oval nucleate cells, attaining 

 in some cases T 2Vo tn °f an 

 inch in diameter, ib. b. The 

 tubules are connected together 

 by a finely fibrous form of 

 areolar tissue, in which their 

 blind ends, or branches, are 

 imbedded. 



The principal arteries of the 

 stomach, derived from the ' cce- 

 liac axis,' are the ( arteria coro- 

 naria ventriculi,' fig. 335, «, 

 which courses along the lesser curvature ; the * gastro-duodenalis,' d 9 

 which gives off the l arteria pylorica,' g ; the ' gastro-epiploica,' 

 ' dextra,' e 3 and s sinistra,' i. The branches of all these arteries 

 have a tortuous course and freely inosculate ; their ramuli per- 



Artcries of the stomach, as seen by raislug it 



CXLVI1I'. 



