ALIMENTARY CANAL OF BIMANA. 



441 



344 



thereto by a progressively decreasing breadth of non-serous wall : 

 the gut then resumes a complete 

 serous coat, which passes off 

 into the progressively widening 

 duplicature of peritoneum, for- 

 ming the ( mesocolon : ' nearing 

 the duodenum it arches across to 

 the left, tc, at the line between 

 the ' umbilical ' and ( epigastric ' 

 regions of Anthropotomy : then, 

 descending ventrad of the left 

 kidney and « quadratus lumbo- 

 rum,'it becomes attached thereto 

 by areolar tissue : it next forms 

 the folds called i sigmoid flexure ;' 

 ib. s F; and, bending to the 

 mid line, contracts and passes 

 as the ' rectum,' r, to the vent. 

 Save at this terminal portion, 

 the longitudinal fibres of the 

 large intestine are specially ag- 

 gregated along three nearly 

 equidistant tracts, one of which 

 runs along the line of attachment of the mesocolon : these ( bands 

 are nearly one-half shorter than the entire 345 



gut, and consequently pucker it up into 

 sacculi. They commence at the setting 

 on of the vermiform appendage and di- 

 verge therefrom to their positions on the 

 cascum and colon : at the sigmoid flexure 

 they begin to expand and form, with added 

 fibres, a strong continuous longitudinal 

 stratum upon the rectum. The circular 

 fibres, uniformly thin and feeble upon 

 the colon, are thickened round the rectum. 

 The human ( vermiform appendage,' fig. 

 345, (j, is commonly from 4 to 5 inches 

 in length : its diameter is about J of an 

 inch : the follicular glands are so nume- 

 rous as to constitute sometimes a conti- 

 nuous layer. The ileum, ib. a, opens by 

 a transverse slit into the inner or mesial 

 side of the caecum, c: the opening being defended by a pair 



Racemose gland ; Human duodenum ; magn. 40 

 diain. cxLVia". 



Cascum and ileo-ctecal val\ 



