Abstract
The compound lateral eye of the adult horseshoe crab, Limulus polyphemus, views the world with approximately 1000 ommatidia. Their optical properties and orientation determine the eye's resolution, field of view, and light collecting ability. Optic axes of adjacent ommatidia diverge from 1-15 deg with an average value of 5.5 deg yielding an average resolution of 0.1 cycles/deg. Resolution is not uniform across the eye: along horizontal planes, it is maximal in the anterior region of the eye (0.22 cycle/deg) and minimal in the posterior region (0.07 cycle/deg); along vertical planes, it is maximal near or just below the horizon (0.23 cycle/deg) and minimal above the horizon (0.04 cycle/deg). Together the ommatidia of one eye view approximately 60% of the hemispheric world on one side of the body. There is little binocular overlap (< 1% of total field). Ommatidial facets of up to 320 microns in diameter (among the largest known in the animal kingdom) make the eye a superb light collector. Limulus are known to use vision to find mates both day and night. Apparently, the optics of the lateral eye sample a large enough part of the world with sufficient resolution and light-collecting ability for the animal to succeed at this essential task.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
