92 CHARM'S V. MOKKII.L. 



somewhat oblique polar view (the entire outer group, e, and six 

 chromosomes of the inner group,/, appeared in one section, the 

 remaining five of the latter group, in the next section). Both 

 groups contain n dyads of which several in / show premature 

 separation of their parts. 



The peripheral position assumed by the w-chromosomes in 

 metaphase (Fig. 3, e, f and g) is again seen in all the anaphase 

 groups (Fig. 3, i and j; Fig. 4, c, d, e and/). This is undoubtedly 

 their normal position in the first polar division. A side view of 

 the final anaphase (Fig. 4, b) shows no peculiar or "lagging" 

 chromosome on the spindle. All the chromosomes divide equally, 

 as the polar views of three final anaphases show, where every 

 chromosome is distinctly visible. 



A single example of the second polar division was found (Fig. 4 

 g). It is a side view of a metaphase with II dyads. In //, the 

 dyads of this group are drawn at three different focal level-. 

 The first polar body (i) of the same egg also contains eleven dyads. 

 In both the second polar spindle and the first polar body, there 

 are two dyads (M and N) somewhat larger than any of the others. 

 These are undoubtedly the products of division of the two largest 

 tetrads of the first polar metaphase (Fig. 3, e and //). The m- 

 chromosome in the second division (Fig. 4, g and //) takes a 

 peripheral position as it did in the first. It appears also in the 

 first polar body (i}. In short there are three chromosomes dis- 

 tinguishable by their size, which can be identified in both polar 

 divisions. These in all probability arise I nun a pairing of the 

 four largest and two smallest oogonial chromosomes. 



Though no anaphases of the second division were found, it U 

 almost certain from the results in Archimerus thai all the d\-. id- 

 divide equally, in a plane corresponding to the constriction shown 

 at metaphase. Accordingly the female pronucleus, as well as 

 the second polar body, will contain 1 1 monads and correspond t<> 

 a spermatozoon bearing the idiochromosome as assumed by- 

 Wilson ('06).' 



3. Pro tenor belfragei. 



The spermatogonial groups have been described and figured 

 by Montgomery ('01 and '<>(>) and by Wilson ('06). Tlir-e ob- 

 servers agree that there are 13 chromosomes, one of which i-^ 



