150 PROFESSOR MARSHALL AND EDWARD J. BLES. 



single section rarely shows the whole length of a nephrostomial 

 tubule. 



By snipping off with scissors small portions from the ventral 

 surface of the kidney of a freshly pithed frog, and examining in 

 normal saline solution, we have seen without difficulty the nephro- 

 stomes in a living condition, and the flagella in active motion. It is 

 noteworthy that in such preparations the current is an outward one 

 through the nephrostome into the body cavity ; and also that the 

 flagella along the whole length of the nephrostomial tubule have 

 their free ends directed outwards towards the body cavity, and 

 not, as in all our sections of hardened kidneys, inwards. 



A further point of great interest in regard to the nephrostomial 

 tubules of the adult frog, concerns the mode of termination of their 

 inner ends. 



Nussbaum, who had previously supported Spengel's view that 

 the nephrostomial tubules in adult Anura open into the fourth 

 section of the urinary tubules, corrected himself in 1880,* and stated 

 as the result of further investigations that the nephrostomial tubules 

 open in young larval Anura into the neck of the Malpighian bodies, 

 as they do throughout life in the Urodeles ; but that in adult Anura, 

 at any rate in the genera Eana, Bufo, and Bombinator, the inner end 

 of the nephrostomial tubule, though it may lie in contact with the 

 neck of a Malpighian body, actually ends by opening into the veins 

 of the ventral portion of the kidney. 



In a subsequent paper, Nussbaum f gives the results of a further 

 investigation by himself and by his pupil Wichmann, which confirms 

 in all respects his. previous account. He also gives a series of 

 excellent figures showing the openings of the nephrostomial tubules 

 into the renal veins in Bana fusca, Bana esculenta, Bufo calamita, 

 and Alytes obstetricans ; and showing also the nephrostomial tubule 

 opening into the neck of the Malpighian body in young larvse of 

 Bana fusca, but separating from the Malpighian body and opening 

 into the renal vein in an older larva of the same species. 



* Nussbaum, " Ueber die Endigung der Wimpertrichter in der Niere der Anuren," 

 "Zoologischer Anzeiger," iii., 1880, pp. 514-517. 



t Nussbaum, " Ueber den Bau und Thatigkeit der Driisen," Part v. ; " Zur 

 Kenntniss der Nierenorgane," "Archiv fur Mikroskopische Anatomie," xxvii., 1886, 

 pp. 466-469, and plate 23. 



