Slide showing a photograph of a 'homozygous Creeper embryo which has lived beyond the lethal period, showing marked changes in legs (only toes showing), wings (less reduced), head and eyes.' Slide shows a black and white photograph of a 'homozygous Creeper embryo which has lived beyond the lethal period, showing marked changes in legs (only toes showing), wings (less reduced), head and eyes. (From Landauer).' The slide is labelled Fig. 140. Late 19th to early 20th century