106 



INTRODUCTION TO CYTOLOGY 



plying nuclei they usually tend to lie more or less parallel. During this 

 middle portion of the prophase a second component of the chromosome, 



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8 



Fig. 54. — Semidiagrammatic representation of somatic mitosis based on studies of 

 species with large chromosomes. 1 , metabolic stage: the chromonemata with anastomoses 

 form a reticulum. 2, early prophase: chromonemata individually distinct and show 

 longitudinal doubleness. Note relation of certain chromosomes to nucleolus. 3, medium 

 prophase: matrix becoming more evident; spindle-attachment regions distinct. 4< later 

 prophase: matrix becoming more chromatic, obscuring chromonemata. 6, metaphase: 

 attachment regions all in equator of spindle formed by karyolymph. 6, anaphase: diver- 

 gence of the chromosomes. 7, early telophase: matrix less chromatic; nucleoli developing 

 in connection with certain chromosomes. 8, medium telophase: anastomoses forming 

 between chromonemata; karyolymph developing; spindle disappearing. 9, later telophase; 

 nuclei larger; reticula more fully developed. For further explanation, see text. 



namely, the matrix, becomes increasingly evident. This is a substance of 

 uncertain history. It is probable that in some form and amount it 



