Ocularium

Many species of Opiliones (or Harvestmen) have a raised bump on the upper (dorsal) surface of their bodies. This bump contains their eyes. Harvestmen have simple eyes (or Ocelli) instead of compound eyes.

By positioning the eyes above the body the animal gets a better view of its surroundings. The eyes face sideways rather than upwards as would be the case if they were on the body itself.

A macro photograph of a harvestman illustrating the ocularium.
Photograph by Dschwen licensed under Creative Commons.

Other names for (or types of) Ocularium include:

• Eye mound
• Ocular tubercle

Related terms

• Ocelli
• Opiliones

Related groups of terms

• Invertebrate body structure

Related pages on this web site

• Arachnids

See other words beginning with O