A, section through the compound eye of a crayfish. Labels: 1, cornea; 2, crystaline cones; 3, retinulae; 4, pigment cells; 5, cuticle; 6, epithelium; n, optic nerve; g, ganglia. B, A single element (ommatidium) from the compound eye of a crayfish. Labels: 1, corneal lens; 2, corneal cells; 3, crystalline cone cells; 4, 5, outer and inner parts of the crystalline cone; p, pigment cells; r, retinula; R, rhabdome; b, basement membrane.

Eye of a Crayfish

A, section through the compound eye of a crayfish. Labels: 1, cornea; 2, crystaline cones; 3, retinulae;…