417 



absorbed. A distinct splitting then appears in the lateral arms which 

 are broad, flat plates that form an acute angle with each other. 

 By this splitting, the 12 broad V shaped chromosomes are divided 

 longitudinally into 24 narrow V shaped chromosomes, 12 of which 

 migrate to each pole of the spindle in preparation for the first 

 maturation division. Occasionally, before the migration takes place, 

 there is seen in some of the chromosomes a second longitudinal division 

 preparatory to the extrusion of the second polar body. 



In a recent paper, Lebrun^) has given the results of his study 

 of the formation of the polar spindles in the eggs of Rana, Triton, 

 Bombinator and Bufo vulgaris; but only in Triton has he been able 

 to obtain a complete history of the late maturation changes. In this 

 paper, Lebrun retracts various statements made in a previous memoir ^) 

 regarding the manner in which the chromosomes divide in preparation 

 for the polar divisions. His new figures of the changes that take 

 place in the egg of Triton previous to the extrusion of the first polar 

 body are strikingly like those I have found in Bufo lentiginosus, and 

 our interpretation of them is the same. I cannot, however, agree 

 with Lebrun in believing that a certain number of the nucleoli 

 escape disintegration to form the chromosomes of the first polar 

 spindle. My investigations show that in Bufo lentiginosus all of the 

 nucleoli are absorbed by the cytoplasm and that they have no apparent 

 connection either with the formation of the spindle or with the 

 elaboration of the chromosomes. 



Bryn Mawr College, 



Bryn Mawr. Pa. Feb. Uth 1902. 



Nachdruck verboten. 



Ueber yitale und sui)ravitale Crranuiafärl)im§- der Nieren- 



epithelien. 



Von Prof. Dr. Julius Arnold in Heidelberg. 



Nach den glänzenden Erfolgen, welche die Untersuchung konser- 

 vierter Objekte aufzuweisen hat, besteht, wie es scheint, bei vielen 

 Histologen wenig Neigung, der Beobachtung des lebenden und über- 

 lebenden Objects, der Methode der vitalen and supravitalen Granula- 



1) H. Lebrux, La vesicule germinative et les globules polaires chez 

 las Anoures. La Cellule, t. XIX, 1902. 



2) Carxoy et Lebrun, La Cellule, t. XVII, 1900. 



Anat. Anz. XXI. Aufsätze. 27 



