No. I.] SPERMATOGENESIS OF BATRACHOSEPS. ^-i) 



Stage of the polymorphous spermatogonia the chromomeres 

 appear a little before the chromosomes. But in the beginnino- 

 of the resting stage there are no traces of any chromomeres. 

 Their formation can be readily followed, and we have seen how 

 they have originated by three chromioles being joined together 

 and surrounded by a film of chromoplasm. Of the chromoplasts 

 we can say but little, as their structure cannot be as closely 

 followed as the chromosomes ; but judging from the presence 

 of the endochromatic granules, it is probable that they never 

 fully lose their identity. There thus remains of the chromo- 

 somic structures only the chi"omioles yet to be considered. 

 These can be readily recognized in all stages of nuclear develop- 

 ment, from the perfect resting stage up to the confluent umbrella 

 stage. In the latter they are rarely demonstrable, which we, 

 however, have reason to suppose is due to their incapacity to 

 stain deeply during this stage. When the new nucleus reap- 

 pears the chromioles are found to have been doubled in num- 

 ber, each chromiole having probably been divided in two. This 

 in itself contradicts any disappearance of the chromioles, but, 

 on the contrary, indicates that the larger structures, the chro- 

 momeres and the chromosomes, must be considered as only 

 temporary structures, originated in order to facilitate the evolu- 

 tion and the division of the chromioles. 



Turning to the linin network, we find that it only exists as 

 such during the prophases of the mitosis and in the resting 

 stages of certain cells. After the equation division of the chro- 

 mosomes, when the usefulness of the linin network has disap- 

 peared, the linin granules scatter all through the cell, and can 

 yet be recognized on account of their staining capacity. When 

 the nucleus is reconstituted and the function of the linin net- 

 work is again required, then the network is re-formed, presum- 

 ably from already existing linin granules. 



What has here been said of the nucleus holds also good for 

 the cytoplasm. We have seen how the two spheres are dis- 

 solved, and later reconstituted, apparently from some of the 

 original granules or their offspring, which in the mean time 

 have been used for the construction of fibers of various kinds. 



As regards the archosomal structures, it appears that they 



