|Description||Slide shows 16 diagrams of 'Permanent Hybrids' of the Drosophila melanogaster (fruit fly).|
Title given at top of slide.
Diagrams are labelled 'A' to 'P'.
Title below image reads 'Fig. 121. - Diagrams showing normal (A) and (B) and variant (C) to (P) chromosome complements of Drosophila Melanogaster. Compiled from Bridges, 1916 (D, E, F), 1922 (G, H, I, J), 1927 (A, B), L.V. Morgan , 1922 (K), Stern, 1929 (L, M, - alternative sex mechanism), Painter and Muller, 1929 (N, O) and Dobzhansky, 1929 (P). Constrictions are emphasised. x ca. 9000. D, E and K the products of primary non-disjunction. F, of secondary non-disjunction. K of fusion. N, O, P of translocation. L and M of deletion with fusion. The structure of the chromosomes is otherwise constant. The XO male and the super-male with super-female forms are sterile, the first for mechnical reasons, the others for physiological reasons.'