Stud. 



les on 



Ch 



romosomes. 



s-^s 



briefly to record the fact that Archimerus, which agrees so closely 

 with Alydus in most other respects, differs from this and all the 

 above-mentioned forms in that the heterotropic chromosome fails 



Figure 3. 

 Archimerus calcarator. — a, Side-view of first division metaphase showing heterotropic chromosome 

 and w-chromosome bivalent; h, polar view of metaphase-group, first division; c, anaphase group, first 

 division, side view; d, late anaphase, first division; e, f, polar views of metaphase-groups, second 

 division, the former including, the latter lacking, the heterotropic chromosome; g, spermatocyte- 

 nucleus, prophase of first division, showing heterotropic chromosome {h), the two separate w-chromo- 

 soraes (m),and five of the sis large bivalents; /;, views of the chromosome-nucleolus (heterotropic chromo- 

 some)at different periods — I, from the contraction-phase of the synaptic period; 2, middle growth-period; 

 3, 4, later growth-period (the last three showing central cavity); /, spermatogonial metaphase-group. 



to divide in the first mitosis, passing over bodily to one pole and 

 dividing equally in the second mitosis, precisely as in the Orthop- 

 tera (Fig. 3, c, d). This fact, which at first I myself hardly found 



