1909. ] POSTCAVAL VEIN IN MAMMALS, 517 
behind the entrance of the left renal, the prevailing Kutherian 
arrangement thus occurring. The lumbar veins are asymmetrical, 
the left vein debouching into the postcaval above the right. 
Text-fig. 138. 
Postcaval vein and its branches in Sciwrus prevosti (A), Hydromys chrysogaster (B), 
and Dipus hirtipes (C). 
Lettering as in text-figs. 132, 133, 137. 
Gerbillus egyptius and Zapus hudsonianus (text-fig. 139, A, B, 
p-519), whichare both members of the group Myomorpha, but which 
are placed by Mr. Thomas * in quite different sections of that group, 
show an interesting point of similarity, of which possibly it is easy 
to exaggerate the importance as a mark of similarity. Posteriorly 
in both animals the postcaval vein lies accurately above the aorta 
* P. Z.S. 1896, p. 1016. 
