GERM CELLS OF ARGAS 651 



of new granules is not by formation de novo, but results from 

 the growth and division of preexisting granules. In stages 

 represented by figures 8, 9, 10 and 11 the mitochondria are of 

 different sizes and the larger granules show irregularities in 

 shape which might be interpreted as indicating constrictions 

 which would lead to division. Moreover, the linear arrange- 

 ment of the granules might be interpreted as representing series 

 of granules which had been produced by division of one or 

 more original granules. However, the granules are so minute at 

 this time that one is not justified in making dogmatic statements. 

 Most of the mitochondria of the cell are concerned in the aggre- 

 gation which forms the ring. Some, however, remain scattered 

 in the cytoplasm. The disintegration of the ring, shown in 

 figures 21, 22 and 23, results from the splitting up of mito- 

 chondrial masses, although the resulting bodies are not as small 

 as the granules which originally formed the ring. 



Extra-nuclear bodies 



The various accounts and discussions which have appeared in 

 recent years relative to the nature and, indeed, the reality of sub- 

 stances in the form of globules, granules, exudations, etc., sup- 

 posedly emitted from the nucleus of various animal cells, give 

 particular interest to the presence of similar structures in the 

 spermatocytes of Argas. It is not my purpose to discuss the 

 literature of this subject here, but merely to state the facts in 

 this particular case with a few brief comparative references. 

 The structures which are designated extra-nuclear bodies (e.b.) 

 appear soon after the stage represented by figure 3 and they 

 vanish shortly before maturation. Figure 3 may be considered 

 as representing a 'pre-etnission' stage. At this time an acid- 

 staining nucleolus, a basic-staining nucleolus and the chromo- 

 somes are the only structure within the nucleus which react to 

 dyes, while within the cytoplasm the mitochondria and the 

 zwischenkorper take definite stains. With the continued growth 

 of the cell small bodies, globular rather than granular, appear 

 within the nucleus and they are also seen within the cytoplasm, 



