ment of the Kidney, and the Development of the - Journal of Cell ...

DEVELOPMENT OF AMPHIBIAN KIDNEY
4G9
P. SUMMARY
The Post-Metamorphie Development of the
Kidney.
1. The principal changes are in the method of attachment of
malpighian unit to archinephric duct.
2. In the anterior region of the kidney there are few functional
units attached to the straight tubules. (Text-fig. 1, A, C, P.)
3. In the middle region of the kidney there are many functional
units attached to the straight tubules. (Text-fig. 1,
B, D, G.)
4. Additional units are produced, after the end of the first
year, only in the posterior region of the kidney.
5. There are no straight tubules in this newly formed posterior
region so that the units become attached to outgrowths from the
archinephric duct. (Text-fig. 1, E, H.)
6. These outgrowths, termed collecting-trunks, branch and
anastomose.
7. Accessory peritoneal funnels are formed from blastema
lying in that part of the kidney which adjoins the gonad.
(Text-fig. 2, C.)
8. These funnels are furnished with longer tails than those
previously produced. (Text-fig. 2, D.)
9. The tails are in close association with renal arterioles
which subsequently pass to excretory units.
10. It is suggested that the arterial supply of the 'tail' may
purify the coelomic fluid which the funnels return to the renal
venules.
The Development of the Vasa Efferentia.
11. The origin of our present conception of the formation of
the vasa efferentia is traced to Gaupp's adoption of Beissner's
compromise between the views of Hoffman and Spengel.
(Pp. 454 to 458.)
12. The gonadic ridge is primitively connected to the region
of the developing kidney by a sheet of kidney blastema. (Textfig.
3, A.)
13. This sheet breaks up into (a) a series of rudimentary vasa