136 ROBERT CHAMBERS, JR. 



The giant nuclei attain their greatest size in testes which are 

 composed almost entirely of islands of spermatocytes in the 

 various stages of maturation but in which no lumen yet exists. 



Simultaneously with the growth of the giant cell the nucleus 

 and noticeably the nucleolus increase in size. A change also 

 takes place in the staining reaction of the nucleus. The chro- 

 matin network, which hitherto together with the nucleolus 

 stained red w r ith safranin, loses that capacity and takes up 



light green, an acid stain. 



A well-grown giant cell thus pos- 

 sesses a large nucleus with an enor- 

 mous basic staining nucleolus and 

 an acid staining nuclear network, the 

 granules in the surrounding cyto- 

 plasm staining red with safranin. 



Similar cells have been described, 

 in literature on spermatogenesis, as 

 rudimentary ova. A significant fact, 

 FIG. 2. however, which militates against such 



an interpretation, at any rate for the 



giant cells in the Simocephalus testis, is that they grow directly 

 from spermatogonia and do not pass through the synapsis stage. 

 The striking but superficial resemblance between these giant 

 cells and growing oocytes is evidently due to the one function 

 common to both, viz., that of an enormous growth in size. 



The ever-increasing size of the nucleolus during growth and its 

 final dissolution in both types of cells favors the assumption 

 that the nucleolus is intimately connected with cell growth. 



In the spermatocytes in Simocephalus where no growth occurs 

 the spermatogonial nucleolus remains small during synapsis and 

 early disappears. The same is true for Pandarus 1 and for Cyclops? 

 On the other hand, in spermatocytes w r here grow r th does occur, 

 a growing nucleolus is described by Schmalz 3 in an Ostracod. In 

 this form the nucleolus grows during synapsis and during the sub- 

 sequent growth period to disappear on the formation of the 

 spindle for the first maturation division. 



1 J. F. McClendon, Arch. f. Zellforsch., V., 1909. 



2 R. Chambers, Jr., Univ. of Toronto Studies, Biol. Ser., No. 14, 1912. 

 J. Schmalz, A rch. f. Zellforsch., VIII., 1912. 



