AECHOPLASM DURING MITOSIS IN LAEVAL SALAMANDER. 195 



directed towards the concavities of tlie horseshoe-shaped 

 daughter-nuclei (figs. 14<, a, 16^ a). 



So soon as the central bodies have reached the archoplasm 

 and become stationary within it (figs. 14, b, 15) that structure 

 steadily grows, becoming fainter and fainter until it has 

 attained the gigantic size represented in figs. 1, 3, 4, 8. A 

 " medullary zone" makes itself apparent about the central 

 bodies, and we are brought back again to that condition of 

 the resting cell from which we started. 



I have not arrived at the same exact conclusions respecting 

 the archoplasmic evolutions in the leucocytes, partly owing to 

 their small size and peculiar granulation, and possibly to some 

 actual diff'erence in the appearance of the spindle and its asso- 

 ciated parts. Nevertheless, I have seen indications of the 

 archoplasm in these cells being drawn out to the lenticular 

 form described in those of the genital ridge. Their central 

 bodies often exist duplicated (fig. 17), and between these bodies 

 stretches that dusky band (fig. 17, a) which we have seen in 

 other cells to represent the embryonic spindle. 



Moreover, from such arrangements of the chromatin as are 

 figured by Flemming in his paper on the leucocyte (op. cit., 

 fig. 2, 6), there is little room left for doubt as to the existence 

 of a spindle, although direct evidence of its presence cannot 

 always be obtained. 



Again, the fan-shaped archoplasms in the leucocytes, such 

 as fig. 20, often present relationships in recently divided 

 elements apparently analogous to the conditions represented 

 in figs. 13 — 16), i. e. they are the collecting fibres of a spindle 

 figure stretching between two separating elements. 



The conclusions of the whole of this part of the inquiry, 

 then, appear to be (i) that with respect to the cells constitut- 

 ing the undifi'erentiated genital ridge of the Vertebrate (sala- 

 mander), Platner's generalisation concerning the spermato- 

 cytes of the Invertebrate (Helix) that " zwischen Knauel- 

 geriist, spindelfasern und Nebenkern ein genetischer Zusam- 

 menhang existirt," is wonderfully borne out ; (ii) that the 

 archoplasm is an accompaniment of the attraction-sphere in 



