i6o 



Edmund B. Wilson 



typically separate, and at first diffuse (as in Anasa or Alydus). 

 Later they condense to from two spheroidal bodies that conjugate 

 in the late prophase to form the central small bivalent and are 

 almost immediately separated again by the division. The idio- 



,% 



% 



a 



d 



h 



FIG. 3 



M. terminalis (Montgomery's material (Nos. 3-11), 2i-chromosome form) 



a, b, first division, polar view (Photo i); c-d, second division; e, f, g, side views of second division 

 (Photos 14, 15); h, sister-groups from the same spindle, in one section, anaphase second division, one 

 showing 10 chromosomes the other 1 1. 



/'-_/, spermatogonial groups, 21 chromosomes; k-l, early and late growth-period. 



chromosome has throughout the early and middle growth-period 

 the form of a single spheroidal or ovoidal intensely staining chro- 

 mosome-nucleolus, which shows in brilliant contrast to the other 

 chromosomes (Fig. 3, k, /, Photo 24). This body is sometimes 

 slightly constricted in the earlier period. Later it is always con- 



