SE 
In a single specimen of Tragulus meminna (ERXLEBEN) recently 
examined by the writer, however, the postrenal division of the post- 
cava was found to lie ventral to the aorta and to be formed caudally 
through a union of the common iliac veins which takes place ventral 
to the aorta (Fig. 2). 
As only one specimen of Tragulus was examined one cannot be 
certain that the postcava in this particular case represents the normal 
conditions; whether it be normal or abnormal, however, the type of 
postcava presented by this single specimen is certainly unusual for 
ruminants and, so far as known to the writer, has not been hitherto 
recorded as occurring in the same. 
The postcava of Tragulus appears to represent a case of double 
or bifurcated postcava. It differs, however, from the type of double 
postcava occasionally met 
Aorta 3 x 
with as an abnormality 
NEE A. renalis in man, the cat and the 
rabbit, and, which is con- 
Aviranalis x ze V. renalis stant in the Indian ele- 
sinistra 
phant and Dasypus setosus 
—~ A. spermatica (Fig. 3), in that the com- 
mon iliac veins (paired 
portion of postcava) do 
A. iliaca ext. not unite to form the | 
Ne unpaired portion con- 
N tiguous to the openings 
/ V. iliaca int, - Of the renalweins,; bus 
aN A. iliaca int. rather at a point some- 
Den ana vision of the! pesicare of what caadal tf Mis lena 
tral view. A type of postcava 
similar to that found in 
Tragulus has also been described by HOCHSTETTER!) as occurring in 
Dasypus novemeinctus (Fig. 4). In this case HocHSTETTER accounts 
for the presence of an unpaired portion of the postcava caudal to 
the openings of the renal veins, as due to the circumstance that, be- 
tween the latter and its point of bifurcation, the postcava undergoes 
an extensive elongation in correlation with a rapid growth of the lumbar 
portion of the vertebral column. In the opinion of the writer this 
explanation is probably correct, not only in the case of Dasypus 
V. renalis 
dextra 
1) Beiträge zur Entwickelungsgescbichte der Amnioten. III. Säuger. 
Morph. Jahrb., Bd. 20 (see p. 620—621). 
