The structure and development of four mutant eyes inDrosophila

Summary

1. The structure and development of four types of mutant eyes inDrosophila melanogaster has been investigated.

2. Infacet the secondary pigment cells are enlarged, and this causes an irregular constriction of the cone-cups and bulging of the facets.

3. Inlozenge-spectacled the cells of the middle layer fail to penetrate between the cells of the outer layer in early pupal life, and later the retinulae fail to penetrate the basal layer.

4. Inophthalmopedia the eye-forming portion of the optic disk in the late larva may be enlarged, and abnormally folded; the folded portion later gives rise not to ommatidia but to a palp of body-surface chitin bearing bristles.

5. The structure and development of themorula eye appears to be identical with that previously described forsplit, except that the cone secretion is normal.