Seemingly blind predator.

Leanchoilia is a four-eyed arachnomorph arthropod known from Cambrian deposits of the Burgess Shale in Canada and the Chengjiang biota of China.
Prominent are large, frontal appendages with long extended whiplike extensions.
Since Leanchoilia was apparently blind (no eye-like structures have yet been found), these appendages helped locate food and keep Leanchoilia informed about its surroundings.
The morphology of the great appendage and the presence of a basipod with strong median armature on the biramous appendages indicate that L. superlata was an active and agile necto-benthic predator (not a scavenger or deposit feeder as previously interpreted).

Middle Cambrian
Burgess Shale
Stephens Formation
Field, British Columbia, Canada
92mm inc appendages on 140mm x 66mm slab
Arthropod, Burgess Shale