120 Taylor — A Morphological and Cytological 



of the equator (Fig. 15). This fact is of importance in connec- 

 tion with making the chromosome counts, for in a precise polar 

 view it eliminates the likelihood of confusing the count through 

 inclusion of both elements of a pair, since the member above 

 completely covers and hides from view its homolog below. 



During anaphase the chromosomes pass to the poles as 

 small, more or less ovoid bodies (Fig. 16). They are figured 

 by Mottier as being elongate, and during the late anaphase as 

 showing the split that so frequently is to be observed in plant 

 chromosomes at this stage. In the writer's material, the better 

 fixed the material appeared, (as judged by lack of shrinkage and 

 especially by the wide and even distribution of the chromo- 

 somes in the plate), the less the chromosomes appeared elong- 

 ated in the anaphase condition. The only elongation that was 

 seen appeared to be due to a tendency of some of the chromo- 

 somes to stick together, probably a fault of fixation, and this 

 increased greatly in material in which clumping of the chromo- 

 somes was present. As for the split, that could not be distin- 

 guished by the writer in any of the species he examined. It is 

 to be noted that these bodies are extremely small: from one- 

 half to one micron only in diameter, and the writer has been 

 unable after long observation to find evidence of bipartition. 



A count of the reduced number at metaphase or early ana- 

 phase is readily made in such a species as Acer negundo, which 

 fixes well and has a small number of chromosomes. This is for 

 the present case given by Darling (4) as thirteen, but in the later 

 paper by Mottier (13) this is questioned, twelve being stated 

 as the probable number, with, elsewhere, fourteen as an alter- 

 native. Why the intermediate count of thirteen should be dis- 

 carded when the investigator seems in doubt whether the num- 

 ber just above or just below that first given is more correct, the 

 present writer fails to see, since there is no especial reason to 

 expect an even number for the reduced count. The material 

 available for the present paper gave ample clear counts of thir- 

 teen to establish this number as the gametophyte chromosome 

 count (Figs. 51-56 inch). 



When the chromosomes approach the poles, they tend to 

 spread out as flattened structures and to anastomose by projec- 

 tions from their edges (Fig. 20). This forms a bowl-shaped 

 structure open on the side facing the equator of the spindle 



