ALIMENTARY CANAL OF BIMANA. 



439 



muscular coat; in fig. 341 the serous coat is marked g. In the 

 interspaces of the villi minute pores may be seen by the aid 

 of the lens : they are the outlets of the ( intestinal tubules,' figs. 

 339, 341, b. Like those of the stomach they are hollow cylinders, 

 fig. 340, closed at the ends, e, which are buried in the areolo- 



340 



tf 



m&^ j&$ 



m&mvl&mv 



341 



m 



j^*=-A*afc 





(7 ~ i ' 



Intestinal tubes from the jejunum niagn. 

 80 diam. cxLVtn". 



Intestinal follicle in vertical section ; magn. 

 40 diam. CXLVIII". 



fibrous tissue: their length is about five times their width, which 

 averages -^oth of an inch : their proper wall consists of nucleated 

 columnar cells, , b ; their mouths d, open into the area of the 

 gut : their contents are a clear fluid and minute granules. Each 

 villus is covered by an epithelium of columnar cells inclosing 

 a parenchyme, with traces of unstriped muscular fibre, the com- 

 mencement of the lacteal absorbents, and a rich supply of 

 .capillary vessels. From the analogy of the gastric tubules it 

 may be concluded that the intestinal ones continue the sol- 



*/ 



vent and alterative operations on the chyme. Other arrange- 

 ments of secreting surface relate to the furnishing of lubri- 

 cating mucus for accessory offices : these are noted as the 

 'follicles.' They are either l solitary,' fig. 341, i, or in groups, 

 termed i agminate,' fig. 342, and such patches appear to be bare 

 of villi. The size and structure of the follicles are the same 

 under both arrangements : they are considerably larger than the 

 intestinal tubules, fig. 341, b; the follicle, 7z, expands as it sinks 

 into the submucous tissue, d, and its broad base is usually 

 applied to the muscular coat, e. The follicles are filled with an 

 albumino-mucous pulp. Fig. 342 gives a moderately magnified 

 view of a patch of ' agminate follicles,' of which patches .about a 



