THE CQSLOM AND MESODERM 



275 



In many mammals, the dorsal mesentery supporting the 

 stomach from the roof of the perivisceral cavity, becomes 



Fig. 127. — Longitudinal section through the trunk of a mammalian embryo, 

 showing the relations of the ccelom and viscera. 



a, anus ; au, auricle of heart ; b, bladder (continuous with allantois) ; 

 bd, bile-duct ; d, diaphragm ; e, liver ; gb, gall-bladder ; i, intestine ; In, 

 lung ; m, metanephric kidney ; oe, oesophagus ; p, pancreas ; pi, pleural 

 ccelomic cavity ; pn, penis ; pr, pericardial ccelomic cavity ; r, rectum ; sc, 

 spinal cord ; s?n, sternum ; sp, perivisceral splanchnoccel ; st, stomach ; 

 t, tail ; ta, truncus arteriosus ; th, thyroid ; tm, thymus ; tr, trachea ; ts, 

 testis ; u, ureter ; uo, opening of urethra ; v, ventricle of heart ; vc, verte- 

 bral column ; vd, vas deferens. 



drawn out into a double sheet of ccelomic epithelium which 

 overlaps the transverse colon of the large intestine on the 

 ventral side. Eventually this sheet may fuse with the 



