The basement membrane of the insect and crustacean compound eye: definition, fine structure, and comparative morphology.

The basement membrane of the compound eye of four insect species and three crustacean species was investigated employing electron microscopy. The basement membrane consists of an extracellular (basal lamina) and a cellular portion, the latter being composed of the flattened terminal extensions of cone cells and accessory pigment cells in insects and distal pigment cells in crustaceans. Other cells can also contribute to the basement membrane. It is thus a complex structure in all well--developed compound eyes. The cellular contributions vary in different species and were found to correlate to specific taxonomic units.