58 



THOS. H. MONTGOMERY jr., 



is that : 2 mantle fibres are attached to each end of each chromosome 

 in the monaster of the 1st spermatocyte; only one mantle fibre is 

 attached to each end of each chromosome in the corresponding stage 

 of the 2nd spermatocyte; and that in the metakinesis of the first 

 division, when the centrosomes of a pair separate, a single fibre passes 

 from each to each chromosome, with the result that the fibres of the 

 two centrosomes intersect. 



There are but few observations on the mode of transposition of 

 the mantle fibres in the metakinesis and dyaster stages of the reduction 

 divisions in objects, where, as in Pentatoma, there are no anaphases 

 interposed between the two succeding divisions. In such cases there 

 are only three thinkable modes of rearrangement of the mantle fibres 

 for the second division, one of which has just been described for 

 Pentatoma, and is represented in the appended diagrammatic woodcut, 

 Figs Ca and Cb. (In this woodcut only 4 chromosomes are delineated. 



for the sake of simplicity.) By a second thinkable mode, at the 

 divison of the centrosome each daughter centrosome would retain two 

 pairs of fibres (Fig. A a); then when the centrosomes had reached 

 opposite poles of the daughter cell, a new set of mantle fibres must 



