No. I.] SPERMATOGENESIS OF BATRACHOSEPS. 89 



the nucleus. The object of this stage is to enable the chromo- 

 plasts to move from one part of the chromosome to another. 

 Thus in the auxocyte it moves from the end of the chromo- 

 some to the angle of the chromosome (Fig. 122). In the 

 umbrella stage, between the spermatocyte and the spermatid, 

 the chromoplasts again fuse together, forming one or more 

 bodies, just as they did in the imperfect resting stage. 



XIII. The central spindle is formed in a different manner in 

 each of the two maturation cells. In the auxocytes it is formed 

 from fibers starting from the centrosphere of the archosome, 

 the first formation appearing between the two halves of the 

 original archosome in the way in which central spindles are gen- 

 erally formed. But in the spermatocytes the central spindle is 

 formed by the approach of two opposite fiber cones. The man- 

 ner of formation of the central spindle observed in the auxocyte 

 has not been seen in the spermatocytes, though it is not impos- 

 sible that it exists there also. 



XIV. The ultimate visible structures of the protoplasm are 

 the individual granules. These granules have the power of 

 adhering together by the means of " linopodia," or small straight 

 arms of protoplasm of the same nature as themselves (Dia- 

 grams 14 and 15). Through the secretion of metaplasmic 

 products these granules are pushed apart from each other and 

 form thus alveoles and vacuoles filled with these secretions. 

 The original granules can so arrange themselves as to form 

 fibers, foams, or reticulum. The alveolar or foam structure is 

 simply an aggregation of alveoles formed in the manner just 

 described. 



XV. The plasmosphere, granosphere, hyalosphere, chromo- 

 meres, chromosomes, spindles, fibers, and linin network are all 

 ephemeral structures temporarily formed for the accomplish- 

 ment of mitosis, which latter process ultimately concerns the 

 chromioles. In the life cycle of every one of the testes cells 

 there is always to be found a period during which the one or 

 the other of these structures does not exist as such, their gran- 

 ula alone remaining, though scattered among other structures. 

 The chromioles, the chromoplasts, the archosome, and the cell 

 wall are the most permanent structures of the cell. But it is 



