ARCHOPLASM DURING MITOSIS IN LARVAL SALAMANDER. 191 



following description of the archoplasmic metamorphosis 

 during mitosis will otherwise be intelligible. Although^ as I 

 have more than once remarked, the archoplasm is most con- 

 spicuous immediately after the division of the cell, it will, for 

 reasons that will make themselves sufficiently obvious in the 

 sequel, be better to begin with that expanded archoplasmic 

 figure characteristic of the period immediately prior to the 

 onset of mitosis (figs. 1, 3, 4). 



At this period, as we have seen, the sphere is built up of its 

 full complement of parts (central bodies, zone, and archo- 

 plasm); as in the spheres of Ascaris ; and to the external surface 

 of the archoplasm there is usually related a fine radiation of 

 the peripheral cell protoplasm (figs. 3, 7, 8). 



A slight concavity presents itself on that side of the nucleus 

 facing the archoplasm, and the chromatin usually presents 

 signs of active metamorphosis. In elements a trifle more 

 advanced, the central body is already divided (fig. 9), and the 

 two halves now recede from one another through the archo- 

 plasm, the intervening portion acquiring a fibrillated appear- 

 ance — the initial spindle of Hermann (fig. 9, a). 



Simultaneously with this divarication of the central bodies, 

 the archoplasm elongates in the direction of their motion 

 until it assumes the pointed ovoid form represented in fig. 9. 



The central bodies continue to recede from one another 

 until they occupy the polar extremities of the archoplasm, the 

 fibrillated appearance of the intervening portion creeping over 

 a greater and a greater area, until it is co- extensive with the 

 contour of the whole mass (figs. 10, 11), when the archo- 

 plasm presents the appearance of a full-sized spindle. 



During all these changes a corresponding disturbance is 

 apparent in the exterior radiation, its fibres showing a marked 

 tendency to follow the central bodies as foci while en route 

 to the polar extremities of the archoplasm, until simulta- 

 neously with their arrival in that position they assume the 

 characteristics of the well-known astral radiations. 



At this juncture the nucleus may or may not have lost its 

 membrane and become looped, but it invariably shows a 



