Some l^tiiits ill the Siieriiiatdji^ciiesis of Miuninalia. 143 



Personally, 1 do not chink this interpretation to be at all correct, 

 for the figures show that it neither arises in conjunction with, nor by 

 the same process as, the Nebenkern (archoplasm) which at the same 

 time exists in the cell. Of the exact mode of origin of this parUcular 

 chromatic body I can say no more than that it will probably prove 

 to be closely analogous to that of precisely similar masses described 

 on i)age 149. In passing, 1 would, however, draw attention to a fact 

 connected with these chromatic bodies in general — viz, that there is 

 always a certain inverse ratio hetiveen their fjroirth and size and 

 the stainahility of the nucleus as a tvhole. 



The spermatocytes when ripe for division contain, then, as in 

 Fig. 3, besides their nucleus and the Lesser Nehenkern, the archo- 

 plasmic portion of the attraction sphere (a), separated from the 

 centrosomes (c), which usually lie between it and the nucleus, and a 

 chromatic body (h. c). 



The spirem figure of these cells is a loosely coiled and twisted 

 thread-work, the individual fibres of which show a disposition to become 

 arranged parallel with respect to one another; and I think we must 

 regard the double rows thus produced (cf. Hermann's figures) as 

 expressive of a potential longitudinal division of the chromosomes 

 (Fig. 2), but at no time is there any indication of a splitting ot solid 

 rods. This parallel disposition of the chromatin bands becomes more 

 and more apparent, by a continual aggregation of microsomes along 

 the two approaching axes (cf. Figs. 2, 3). As development proceeds 

 the irregular number of long double coils produced (Fig. 2) become 

 gradually thickened, and eventually separate into eight dense masses 

 (Fig. 3), the formation of these eight chromatic loops being presumably 

 brought about by the fusion at determinate positions of the irregular 

 pre-formed double threads. I have discovered no such radial dispo- 

 sition of the chromosomes Avith respect to the nucleolus as is described 

 by Julin; but there is a somewhat similar arrangement in the achro- 

 matic radiations appearing round the chromosomes, to that which 

 Rückert has likened^) to a bottle-brush ("goupillon") and to which Julin 

 draws attention, in relation to the chromosomes of Ascidiaus. 



^) Aiiat. Anz. Bd. VII. 1892. p. 107. 



