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be in place to briefly point out the leading features of the above 
mentioned types of renal anomaly, based on the more recent literature. 
Dystopia renis, or dystopy of the kidney, is of two forms: D. 
renis sagittalis, and D. renis transversa. In the former there is a 
displacement of one or both of the kidneys in a cephalo-caudal direc- 
tion, giving rise to what is commonly called pelvic kidney. In the 
latter there is a displacement horizontally, i. e., from side to side, as, 
for instance, when the right kidney becomes displaced to the left side, 
and vice versa, there occurring some degree of variation. It is with 
the first form that we are here concerned. 
In D. renis sagittalis, as recently emphasized by SCHoENLANK, there 
is to be distinguished, (1) the primary pelvic kidney, in which the 
definitive renal arteries and veins arise further caudad than the normal 
level, having their source near the level of the Arteria mesenterica 
inferior. But they may arise even further caudad, from the A. iliaca 
communis, the sacralis media, or the hypogastrica; (2) the secondary 
pelvic kidney, where the organ has been displaced to the pelvic region 
secondarily, after having first attained the normal level, the renal 
blood-vessels in such case arising at the normal places of origin. 
The causes that have been suggested for primary pelvic position 
of the kidney are various. It may be due to an arrested elongation 
of the developing ureter whereby it holds back the kidney, so to 
speak, and prevents its forward migration. Again the kidney may 
remain permanently pelvic through mechanical agency of neighboring 
organs during the changes in position which these organs undergo 
in the course of their development, although these movements may 
be entirely normal in themselves. The ureter in such instances would 
increase in length to the normal, resulting in a more or less coiled 
or convoluted condition. 
The secondary form of pelvic kidney may result when the kidney 
pushes to an unusual degree into the body-cavity, so that its peri- 
toneal covering assumes the relations of a mesentery. This leaves the 
organ more or less freely movable (floating kidney) and subject to 
the influence of movements of surrounding organs. Its own weight 
may play an important part. Such a kidney may become fixed in 
the pelvic cavity and thus constitute a secondary pelvic kidney, but 
it may also be displaced in other directions. 
The renal blood-vessels, artery and vein, it appears, while perhaps 
offering the chief resistance, are in themselves insufficient to prevent 
