THE VITAL PHENOMENA OF THE CELL 



191 



independent individuality. The angles of the loop are turned 

 towards the original pole (the polar area in the Salamandra) , 

 whilst the ends of the loop, which are knob-like and swollen, are 

 directed towards the region of the anti-pole. 



The second stage of division now commences. The centro- 

 somes, with their spheres, separate and travel for some distance, 

 until their common axis lies either somewhat obliquely or parallel 

 to the first division plane., The nuclear membrane dissolves. 

 The four segments arrange themselves in the equator between the 

 two centrosomes in the manner described above, whilst a dis- 

 tinct radiation develops around the centrosomes in the proto- 

 plasm, so that the appearance, seen from the pole, resembles that 

 depicted in Fig. 85 A. The four segments then split longitudinally 



FIG. 85. A. Four mother-segments seen from the pole of the unclear figure (after V;an 

 Beneden and Neyt, PI. VI., Fig. 16). B Longitudinal splitting of the four mother-seg- 

 ments into eight daughter-segments (after van Beneden and Neyt, PI. VI., Fig. 17). 



that is to say, the third stage commences (Fig. 85 B). The 



daughter segments thus formed separate from one another, and 



travel towards opposite poles. E. van Beneden (VI. 4b) and Boveri 



(VI. 6) consider that the spindle fibrils play an active part in this 



process. In their opinion, the spindle in Ascaris is composed of 



two independent portions, each of which consists of a large 



number of protoplasmic fibrils. These 



converge towards the centrosome and 



attach their ends to it, whilst the op- 



posite ends diverge, approach the nuclear 



loops, and fasten themselves at various 



points to the daughter-segments, which 



are turned towards them. These threads 



by gradually contracting, and thus be- 



coming shortened, cause, in van Beneden's 



and Boveri's opinion, the separation of 



the four daughter-segments, which are have attached themselves to 



thus gradually drawn towards the cen- the daughter-segments. (After 



van Beneden and Neyt, PI. 



trosomes. vi., Fig. 8.) 



FIG. 86. The construction 



