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INTRODUCTION TO CYTOLOGY 



each composed of two substances differing in chromaticity, are scattered 

 throughout the cytoplasm. At each of the meiotic divisions they break 

 up into fragments (dictyosomes) which become arranged around the 

 nucleus at the equator of the cell and pass as equal groups to the two poles 

 in advance of the chromosomes. In Gerris Pollister finds that only the 

 osmiophilic substance forms the dictyosomes, the osmiophobic (and 



Fig. 130. — Diagram illustrating principal features of spermiogenesis in animals, a, 

 acrosome; c, centrioles; g, Golgi material (acrobiast) ; N, nucleus; n, nebenkern; p, perfora- 

 torium. {Based on diagrams and other figures of Bowen.) 



neutral-red staining) substance remaining behind. In another series of 

 forms (mollusks, amphibia, other vertebrates) the Golgi bodies are closely 

 aggregated about the centrioles where their lightly staining substance 

 flows together to form the idiosome, to the surface of which their deeply 

 staining constituent adheres as separate chromophilic rodlets. This 

 chromophilic matter often appears as a network or a continuous shell 

 instead of separate rodlets, but it is uncertain how far such appearances 

 are due to the action of fixatives. It was formerly thought that the idio- 

 some substance was related primarily to the centrioles, the Golgi materia] 



