﻿2 54 BOTANICAL GAZETTE [april 



modes of attachment to the spindle fibers. In Lilium the most 

 frequently occurring form of chromosome at this stage is that of 

 the two segments rather closely applied and twisted upon each 

 other. They, are attached to the spindle at the end, and stand 

 radially to its long axis {fig* 2, a). The segments are fre- 

 quently straight and not twisted upon each other. 



Numerous instances are met with in which the daughter 

 segments remain adhering at both ends, but separate near the 

 middle, so that a ring or loop results (fig. 2, b). The segments 

 may separate at one end, when an open ring or loop is formed. 

 Cases are not infrequently observed in which the segments of 

 the ring-shaped chromosomes bend near the middle so that the 

 free ends are brought nearer together, and we have a ring or 

 loop partly folded upon itself. This is true in a measure in 

 fig, 2, b. The ring- or loop-shaped chromosome is attached to 

 the spindle near one end of the daughter segments, or at a 

 point midway between the ends, rarely at the ends; although 

 such a mode of fastening was occasionally observed. As a rule, 

 however, the rings or loops are placed tangentially upon the 

 spindle. 



When the daughter segments diverge at one end but remain 

 closely applied for the remainder of their length, a Y-shaped 

 chromosome results {fig. 2, h), which is fastened to the spindle 

 as indicated in the figure. An X-shaped chromosome is formed 

 when the segments lie variously crossed with one or both ends 

 diverging [fig. 2, f), X-shaped chromosomes are not rare in 

 which the segments are so closely applied at one end as to give 

 the impression of a loopformed by the chromosome folding in 

 such a way that the opposite ends are brought together {fig. 2, g) . 

 . In fact all intermediate forms are found between that of /and ^. 

 Finally chromosomes such as ^g. 2, c, d, e are of frequent 

 occurrence. In this form of chromosome, the segments, which 

 are more or less twisted upon themselves, are usually fastened 

 to the spindle fibers near one end or at the middle. Such 

 chromosomes are, as a rule, oriented tangentially upon the 

 spindle. 



As regards the development of the spindle, I have nothing 



