. The chromosomes. Chromosomes. THE GENERAL OUTLINE OF METOSIS 63 posed becoming ' spiralized ' ; that is to say each prometaphase or metaphase chromatid at mitosis consists of a cylindrical ' spring ', possibly enclosed in some sort of sheath or pellicle. By special tech- nical methods (exposure of the living material to ammonia vapour or fumes of strong acids before fixation) it has been shown ^^' ^^ that at meiosis. Fig. 15.—Diagram of a bivalent at the first meiotic division showing the major and the minor spiral. The spindle attachments are subterminal and there is only one chiasma. each
. The chromosomes. Chromosomes. THE GENERAL OUTLINE OF METOSIS 63 posed becoming ' spiralized ' ; that is to say each prometaphase or metaphase chromatid at mitosis consists of a cylindrical ' spring ', possibly enclosed in some sort of sheath or pellicle. By special tech- nical methods (exposure of the living material to ammonia vapour or fumes of strong acids before fixation) it has been shown ^^' ^^ that at meiosis. Fig. 15.—Diagram of a bivalent at the first meiotic division showing the major and the minor spiral. The spindle attachments are subterminal and there is only one chiasma. each chromatid probably forms a double spiral (Fig. 15), each g3rre of the ' major ' spu'al being made up of several gyres of the ' minor ' spiral. This may also be the case at mitosis, but so far only one spu-al has been observed at ordinary somatic divisions. Metaphase of First Meiotic Division At mitosis each chromosome is attached to the spindle by a single spindle attachment (or one which. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original White, M. J. D. (Michael James Denham), 1910-. New York, Chemical Pub. Co.
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Keywords: ., bookcentury1900, bookcollectionbiodivers, booksubjectchromosomes
