No. 399. ] FREQUENCY OF ABNORMALITIES. 187 
Five cases of persistent posterior cardinal veins were met 
with by the writer in twenty-five cats examined. In three of 
these cases the left common iliac vein (V. iliaca communis si- 
"istra) was absent, and in two it 
was present. 
(a) PERSISTENT POSTERIOR 
CARDINAL VEINS. LeEFr Com- 7 
MON ILiAc VEIN (V. iliaca com- 
munis simistra) ABSENT. 
The three examples of this 
type were essentially the same 
in character and are well repre- 
sented by Fig. 1. 
In each instance the union of Dextra Sinistra 
the two posterior cardinals (17) 
with the common postcaval vein 
(1) took place in the neighbor- 
hood of the kidneys. In two 
instances this union was opposite 
the third lumbar vertebra, and 
in one, opposite the fourth. In 
the former the right renal veins, 
single in one case and double in 
the ether, opened into the right Fte. :.— Princeton. Morphological Museum, 
. i . No. 6or. Ventral aspect. V. cardinalis 
posterior cardinal; in the latter 4,44 and sinistra persistent. V. iliaca 
(Fig. 1) the right renal vein (7) «wis sinistra lum D nas 
opened into the common post- zia interna. s. V. sacralis media. 6. 
cava. (1). (earum CARA. suite libre 
a Sach instance, as in Fig. f Geen A. iL me "ir 
thesingleleftrenalvein(7)opened sacralis media. 17. V. cardinalis post. 
intotheleft posteriorcardinal(17). . 
The middle sacral vein (V. sacralis media), Fig. 2 (5), in each 
of these three cases, was connected with the posterior cardinal 
veins (17) in a characteristic manner. It opened into the 
angle of union of two veins which joined, respectively, the 
right and left posterior cardinal veins (17) at varying dis- 
tances from the point of union of the external and internal 
iliac veins, 
