A new method (called New Relative Length) was developed for comparison of chromosome size when both paired and impaired chromosomes are present. All chromosomes were used in the calculation. A method of graphical display of karyotype data (called a Karyotype Graph), plotting New Relative Length on the vertical axis and arm ratio on the horizontal axis was used to indicate sampling error, to pair chromosomes and to match similar chromosomes in related species. Terms for Chromosome Size were also defined namely Small, Medium or Large depending on New Relative Length as a proportion of total chromosome length. These terms could also be used to compare chromosomes within species and between related species.