148 PROFESSOR MARSHALL AND EDWARD J. BLES. 



of the nephrostomes in his well-known and admirable essay on the 

 Urinogenital Organs of Amphibians*. He repeated Meyer's method 

 of treatment with silver nitrate, but obtained the best results by 

 means of chromic acid. He describes the nephrostomes in Bana, 

 Bufo, Bombinator, and Discoglossus, and gives excellent figures of 

 surface views of the kidneys of Bana temporaria and Discoglossus 

 pictus, showing the actual arrangement of the openings. The nephro- 

 stomes are confined to the part of the kidney covered by peritoneum, 

 i.e., to the ventral surface and inner border ; they are arranged along 

 definite lines or tracts, usually following the renal veins, and they 

 are more numerous in the anterior than in the posterior part of the 

 kidney. They are often placed in groups opening into shallow 

 depressions of the kidney surface, and from 200 to 250 can be 

 counted in a single kidney. A single nephrostome may lead into 

 two or three tubules ; or a single tubule on reaching the surface may 

 branch and open by two or more nephrostomes. 



Spengel notes that although the nephrostomes can be seen with the 

 greatest ease either in surface views or in sections in any plane, yet 

 that he experienced the greatest difficulty in trying to trace them into 

 connection with the kidney tubules. In Coecilise and in Urodeles he 

 followed the nephrostomial tubes repeatedly and without difficulty 

 into the necks of the Malpighian bodies ; but in none of the genera 

 of Anura examined by him, Bana, Bufo, Bombinator, and Discoglossus, 

 was he able to trace such a connection. Examination of sections 

 in various planes, injection of the urinary tubules, and teasing of 

 fresh specimens, all alike failed to show any communication. In one 

 single instance, in a transverse section of the kidney of Bufo cinereus, 

 did he satisfy himself of the existence of a tubular communication, 

 and that was not between the nephrostomial tubule and the neck of 

 the Malpighian body, but between a ciliated tubule and the fourth 

 section of the urinary tubule, i.e., the collecting tubule. The ciliated 

 tubule was, however, not traced to a nephrostome, and so even this 

 solitary instance is not a proved case. 



Spengel, however, considers it probable that the connection in this 

 instance is a real one between a nephrostomial tubule and the fourth 



* Spengel, " Das Urogenitalsystem der Amphibien," Part i. ; " Der Anatomische 

 Bau des Urogenitalsystems," Arbeiten, a.d. ; Zool. Zootom., Institut. der Univ. 

 Wiirzburg, Bd. iii., 1876, pp. 82-89. 



