568 
R. RUGGLES GATES AND NESTA THOxMAS. 
AIeiotic Divisions. 
(E. rubricaly X, 
Fig. 16.— Typical heterotypic spindle in profile, showing 14 chromo- 
somes somewhat irregularly scattered on the equatorial plate. 
Fig. 17. — Polar view of heterotypic spindle, showing 14 chromosomes 
lying in several planes. 
CE. lata ruhricalyx. 
Fig. 18. — Diakinesis, showing 15 chromosomes and two small nucleoli. 
Fig. 19. — Heterotypic spindle in profile, with the 15 chromosomes 
irregularly arranged. A great variation in the size of the chromosomes 
may be observed. 
Fig. 20. — Polar view of heterotypic nucleus at the metaphase stage, 
showing 15 small chromosomes lying in vacuolate protoplasm. 
Fig. 21. — Metaphase group of 15 chromosomes. The cells show 
signs of degeneration. 
Fig. 22. — Typical anaphase of heterotypic division. The spindle was 
cut and only 11 chromosomes are seen in the section, but these all 
show the longitudinal fission. 
Fig. 23. — Interkinesis. Seven split chromosomes and a nucleolus are 
contained in the nucleus. An eighth chromosome may be seen just 
outside the nuclear membrane. 
Fig. 24. — Polar views of the two groups of chromosomes in the homo- 
typic metaphase. Each group contains 7 whole chromosomes and 
a ^ chromosome. Several of the whole chromosomes show the longi- 
tudinal split, and in the right-hand group the two halves of one chromo- 
some are rather widely separated from each other. The distribution 
hei’e represented has resulted from the longitudinal division of a 
chromosome, presumably the extra one, on the heterotypic spindle. 
S indicates the two halves of this chromosome. 
Fig. 25. — Homotypic metaj)hase in polar view. Cell and chromosomes 
exceptionally small. The left-hand group has clearly 7 whole and 
one A chromosomes, while the right-hand group consists of 6 whole 
chromosomes, a ^ chromosome and a small fragment. Not including 
the fragment there are 14 chromosomes pi-esent in the two nuclei. 
The fifteenth may be seen in the protoplasm between the two nuclei, 
having failed to enter the right-hand nucleus. S indicates the halves 
of the chromosome which split in the first division. 
Fig. 26. — Profile view of typical homotypic spindle. 
Fig. 27 a and h . — Two homotypic anaphase spindles in iDrofile, from a 
