226 Georgina Sweet : 



asserted that ther open into the Renal Veins. 

 This statement mu>t be accepted with caution. 

 It appears more probable that they have lost 

 their connection with the renal tubules, and per- 

 sist as ciliated cups on the surface of the kidney." 



1906. Holmes, ['06, p. 204] accepts the internal opening of 

 the nephrostomes as into the branches of the 

 Renal Vein. 



It was then with the hope that our Australian forms might 

 throw some light on this problem, that this part of the Avork 

 has been done. 



Sh lecture. 



In general external form and position, the kidneys of the 

 forms examined do not differ materially from those of Rana, 

 being flattened bodies, three to four times as long as they are 

 broad, and one-third to one^quarter of their width in thickness. 

 [Hee Pi. XX., fig. 1.] Situated just ventral to the dorsal l)ody wall, 

 in the a,bdominal lymph space, they are covered ventrally by the 

 peritoneum which keeps them in position agaimt the dorsal 

 body wall. The ventral surface is generally flat or occasionally 

 distinctly concan^e, while the dorsal surface is always more or 

 less convex. The outer edge of each kidney i.s formed by the 

 ureter which arises by branches in the substance of the 

 kidney, and runs back behind the kidney dorsal to the large 

 intestine, to open into the roof of the cloaca. 



Blood-vessels.— The Kenal Arteries vary in number, being 

 generally in 5 or 6 pairs. They enter the kidney usually at 

 about one-third of its width fr(un the inner edge, and break up 

 i(it once into numerous branches. Somewhat dorsal to the ureter 

 runs tlie Renal Portal Vein often receiving one or more lumbar 

 veins fr(un the body wall. This vein breaks up into numerous 

 branches running inwards acr.)ss tlie dorsal surface of the 

 kidney, breaking uj) ais they do so. The Renal Veins arise on 

 the ventral surface of the kidney, sometimes nearer to the 

 inner edge than the entrance of the Kenal Arteries (e.g.. in 

 Crinia signifera). More often these veins leave the kidney 

 on the outer side of the arteries (e.g., in Hyla aurea, Pseudo- 

 pliryne australis, Heloiojiorus pictus, Notaden bennetti, and 



