442 WESLEY R. COE, 



occurs. The majority of the chromosomes assume in the equatorial 

 plate the form of rings, many of which are elongated in a directioQi 

 parallel with the axis of the spindle. In many cases they are ir- 

 regularly diamond-shaped with the corners enlarged. At a more ad- 

 vanced stage they are drawn out into dagger-shaped bodies as 

 KlinckowstrÖxM describes for Prostheceraeus. No matter what may 

 be the form of the chromosomes, it is nearly always found that the 

 portion which lies on one side of the equator has its counterpart on 

 the other side (Fig. 17). In all cases a very conspicuous, and 

 sometimes deeply staining, fibre runs from the ends of each chromo- 

 some to the centrosphere of the same pole of the spindle. These 

 fibres seem to be attached directly to the ends of the chromosomes, 

 and are in some cases so coarse and deeply stained that the end 

 attached to the chromosomes appears at first sight to be a continuation 

 of the chromosome itself. The fibres of the central spindle stain much 

 more faintly, but may often be followed directly from pole to pole. 



Shortly after the division of the chromosomes the daughter seg- 

 ments assume the form of simple, short rods; and the two groups 

 are eventually gathered respectively into the equatorial plate of the 

 spindle within the first polar body and into that of the second polar 

 spindle. I was quite unable to gain any new light in regard to the 

 reduction of the chromatin. 



After the first polar body is fully formed the centrosomes con- 

 tained therein pass to the opposite ends of the elongated body and 

 a spindle is formed between them (Figs. 19, 22). The centrosomes 

 are without radiations other than those of the spindle. The chromo- 

 somes are drawn into the equator of the spindle, and divide into 

 two groups which pass to opposite ends of the polar body (Fig. 28). 

 Sometimes the process of division is carried still farther and the 

 cytoplasm of the cell divides also, and two polar bodies result from 

 the karyokinetic division of the first, as Griffin finds sometimes 

 occurs in Thalassema (7), Kostanecki in Myzostoma (7), and Kosta- 

 NECKi k Wierzejski (15), MacFarland (18) and others for Mollusks, 

 etc. ^). The first polar body, although much larger than the second, 

 is, nevertheles, very small in compaf-ison with the egg-cell, and much 

 smaller than is found in most animals. It varies considerably in size, 

 but averages less than ^'^ of the diameter of the egg-cell. It has, there- 



1) Garnault finds that this division may be carried even farther, 

 and in place of two or three polar bodies he has sometimes found as 

 many as six. 



