406 



GENERATION. 



FIG. 44. 



length and becomes convoluted. It is held loosely to the 

 spinal column by the mesentery, a fold of the peritoneum, 

 this membrane being reflected along the walls of the abdom- 

 inal cavity. In the early stages of development, a portion of 



the intestine protrudes at the um- 

 bilicus, where the first intestinal con- 

 volution appears ; and sometimes 

 there is a congenital hernia of this 

 kind at birth, which usually disap- 

 pears under the influence of gentle 

 and continued pressure. An illus- 

 tration of this is given in Fig. 44. 

 This protrusion, in the normal pro- 

 cess of development, is gradually 

 returned to the abdomen, as the 



Foetal pig, showing a loop of intestine, Cavit 7 f the ' pedicle of the U1H- 



bilical vesicle is obliterated, at about 

 the tenth week. 



At the upper part of the ab- 

 dominal cavity, the alimentary ca- 

 nal presents two lateral projec- 

 tions, or pouches. The one on the left side, as it increases in 

 size, becomes the greater pouch of the stomach ; and the one 

 on the right side, the lesser pouch. 



At a short distance below the attachment of the pedicle of 

 the umbilical vesicle to the intestine, there appears a rounded 

 diverticulum, which is eventually developed into the caecum, 

 or the commencement of the larger intestine. The caecum 

 gradually recedes from the neighborhood of the umbilicus, 

 which is its original situation, and finally becomes fixed, by a 

 shortening of the mesentery, in the right iliac region. As the 

 caecum, or caput coli, is developed, it presents a conical append- 

 age, which is at first fully as large as the small intestine, and 

 is relatively longer than in the adult. During the fourth 

 week, this appendage becomes smaller and more or less twisted, 

 forming the appendix vermif ormis. At the second month, the 



firming an umbilical hernia ; from 

 a specimen in the possession of 

 Prof. Dalton. From the convexity 

 of the loop, a this filament is seen 

 passing to the umbilical vesicle, 

 which is here flattened into a leaf- 



