244 H - M - KINGERY. 



observed. Some of the chromosomes divide earlier than others 

 and consequently the metaphase is not so distinctly marked as 

 in some forms. A few instances of a telophase were seen, in 

 some of which both groups of daughter-chromosomes are in the 

 oocyte, with no indication as yet of a division of the cytoplasm 

 to form the polar body, while in the others the constricting off 

 of the polar body may be plainly seen. After the first polar 

 body is formed the chromosomes remaining in the oocyte do not 

 form a resting nucleus but at once enter the second polar spindle. 



The second polar spindle, as stated above, is of about the same 

 length as the first, while only two thirds or three fourths as much 

 in diameter. The chromosomes as seen in the equatorial plate 

 stage are short and rod-like and straight or slightly curved. 

 They are not as long or as much curved as Kirkham describes in 

 the second polar spindles of normally maturing oocytes. The 

 chromosomes are arranged with their long axes parallel to that 

 of the spindle itself and as in the first polar spindle are scattered 

 in a plane at right angles to the length of the spindle. This 

 differs from Kirkham's account of the normal second polar 

 spindle, in which he states that in general the chromosomes lie 

 with their long axes across the spindle. In the spindles of these 

 degenerating egg-cells some of the chromosomes are constricted 

 across the middle in preparation for division, having the appear- 

 ance of elongated dumb-bells; others have not started to divide 

 and have the typical rod-like form. Others still have already 

 divided and are short and thick, their length only slightly exceed- 

 ing their diameter. (See Figs. 3 and 4.) This division as well 

 as the first is apparently transverse in the mouse. The chromo- 

 somes are crowded together, as in the first polar spindle, making 

 an accurate count difficult; there are from twelve to thirty, 

 owing to the fact that some divide sooner than others. 



Descriptions of the appearance of the second polar spindle are 

 as conflicting as those of the first. Sobotta states that in 

 normally maturing oocytes there are neither centrosomes nor 

 polar radiations. Lams and Doorme describe centrosomes but 

 say that polar radiations are absent; Kirkham states that both 

 centrosomes and polar radiations are present in some cases. 

 In second polar spindles of degenerating oocytes Athias states 



