ARCHOPLASM DURING MITOSIS IN LARVAL SALAMANDER. 189 



genital ridge of the salamander, while yet undiflferentiated to 

 form either ova or spermatozoa, shows that this structure 

 cannot bear any special relation to the spermatocytes; while 

 its occurrence, as I have shown, in cells at once so widely dif- 

 ferent from these, and primitive, as the leucocytes, exclude it 

 from any peculiar relation with the reproductive elements at 

 all, and speaks volumes for its probable existence in all 

 the intermediate tissue forms. 



From the similar appearance and relationships of the archo- 

 plasm ("Nebenkern^' of Platner) in Vertebrates and Inverte- 

 brates alike, and from the wide distribution and appearance of 

 this structure wherever the conditions favour the elucidation 

 of the sphere, I confess I see no alternative but to regard the 

 archoplasm as a normal accompaniment of the period of com- 

 parative repose that marks the resting cell. 



The foregoing comparison between the spheres and their 

 constituent parts in these various animal cells, might appear 

 pedantic, and in the present state of our knowledge unne- 

 cessary, if it were not that some of these parts are pro- 

 bably, as we have seen, the fleeting expression of metamorphic 

 phenomena ; while others, such as the central bodies, though 

 dividing, retain their characteristics unimpaired. 



It will have become obvious that the archoplasm ('^Ne- 

 benkern" of van Beneden), when considered independently 

 of its enclosed zone or central body, undergoes a cycle of 

 changes of form and size, each corresponding more or less 

 closely with changes proceeding in the nucleus itself, on its 

 passage from a condition of complete repose to one of active 

 mitosis. 



It should be borne in mind, however, while discussing this 

 question, that the successive archoplasmic phases by no means 

 invariably keep pace with the corresponding nuclear meta- 

 morphoses. 



For example, as Flemming has pointed out,^ so marked a 

 feature as the divarication of the central bodies, and the 



• 1 " Attraktionsspharen und centralkorper in Gewebszellen und Wander- 

 zellen," ' Anatomischer Anzeiger,' 1891, pp. 79, 80. 



