460 BOTANICAL GAZETTE [December 



include small granules. An attempt has been made to trace these 

 structures from their origin to their fate, in order that something 

 regarding their nature and function might be determined. This 

 complexity of structure is in contrast with the prophase of an ordi- 

 nary mitosis, where only chromosomes, at most chromosomes and 

 the nucleolus, are inclosed by the nuclear membrane. 



The dark vacuolate masses are most conspicuous just after 

 fusion (fig. 27). In the early stages small refractive globules are 

 scattered throughout the granular egg nucleus ; later, these become 

 inclosed in a gelatinous network (fig. 19), and next appear as pre- 

 viously described. During the first mitosis they accumulate into 

 several globular, vacuolate bodies (fig. 34). The latter decrease in 

 volume or become distributed throughout the nucleus during meta- 

 phase (fig. 46). At anaphase the irregular masses once more 

 become conspicuous (fig. 51). When the daughter nuclei are 

 formed, these bodies are not included, and soon disappear. The 

 fact that they are extruded would seem to indicate that they are 

 not fundamental nuclear material. The fact that they are stored 

 up during the growth of the nucleus and decrease in amount during 

 mitosis would suggest that they are simply stored food bodies. 



Two successive groups of intranuclear fibers become differen- 

 tiated during the processes of fusion, and the first division after 

 conjugation. The first is concerned with the approximation of 

 chromosomes to be described later; the second with the first 

 mitosis. While the two chromatin groups, from the egg and from 

 the male nucleus, are still distinct, fibers which penetrate and 

 surround these groups are organized (fig. 28). A union of the two 

 groups of fibers results in the formation of a single spindle made 

 up of large complex strands (figs. 29-33). The spindle drawn was 

 60 im in length. After the approximation of the chromosomes into 

 pairs the spindle broadens; the fibers become less conspicuous, and 

 finally disappear, leaving a group of irregularly arranged chromo- 

 somes within the now much reduced nuclear space (figs. 43-45). 

 Meanwhile the chromosomes migrate to the center of the nucleus, 

 and soon the second set of fibers is formed (fig. 46) . At first these 

 are restricted to the region in which the chromosomes are situated; 

 as the chromosomes move to the poles, the whole nucleus becomes 



