THE ORIGIN AND DEVELOPMENT OF GASTRIC GLANDS. 93 



enon " -the presence of these ovoid cells throughout all the 

 glands of the embryo stomach. These round cells do appear 

 throughout the whole stomach wherever glands are to be formed, 

 at the pyloric, cardiac and fundic regions in all three types exam- 

 ined. They are, as has been stated, the gland anlages, and are 

 to form the functional portion of the glandular epithelium. A 

 pig embryo of 10 cm. shows these round or " ovoid " cells at the 

 base of the gland, resting upon the basement membrane (Fig. 

 32, /"). A section through a pig of 14 cm. shows them still 

 further depressed from the surface, appearing more truly gland 

 shaped (Fig. 30, /"). In this stage the glands are beginning 

 to subdivide. Division takes place at the base of the gland 

 and also along the sides of the fundus of the gland. Cells pro- 

 liferate and project up into the lumen of the gland supported by 

 connective tissue outgrowths. Several glands may thus come 

 to open into one duct by the formation of these new outgrowths. 

 These, in their turn, are subdivided by similar outgrowths. As 

 all these open at the neck or in the fundus of the gland, com- 

 pound glands are formed from what were originally simple tubes. 

 This also takes place in the same manner in Desmognathus and 

 Amblystoma. 



In tracing the development of the earlier stages of the glands 

 the whole stomach could be sectioned. In most cases the 

 pancreas was left attached as it also assisted in rendering orienta- 

 tion easier. In pigs of more than i 2 cm. total length portions 

 were taken from different parts of the stomach, as cardiac, fundic 

 and pyloric regions. Here, as in the earlier stages, glands were 

 traced from section to section, every precaution being taken not 

 to confuse them with one another, by taking accurate measure- 

 ments of all the sections. 



SUMMARY. 



The surface epithelium presents, at first, a stratified appearance, 

 but soon becomes a single layer with nuclei approximately in the 

 center of the cells. The stomach glands are formed from round 

 granular cells lying at the base of the surface epithelium. These 

 round cells divide and multiply, forming around a central lumen, 

 while at the same time causing an insinking of the epithelium of 

 the surface to form the excretory duct, by lateral displacement of 



