Cephalopoda Glossary
The usual position of the eye is within the head. Sometimes eyes may bulge out from the head somewhat but these are still called sessile eyes. The eye generally occupies nearly the full thickness of the head as seen in the first picture on the right. However, in a few species of decapodiforms and some octopods, the eye is greatly reduced in size as seen the preserved squid on the far right. Note the small eye-opening of this squid that is puckered into a small papilla on the side of the head.
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Figure. Left - Side view of the head of Abralia trigonura (fam. Enoploteuthidae). Right - Side view of the head of Promachoteuthis sp. C (fam. Promachoteuthidae).
In the family Cranchiidae, young squids often have the eyes on long stalks. These stalked eyes and their associated optic lobes extend well lateral to the head. The optic lobes connect to the central brain by long optic nerve stalks that can be seen in the photographs below.
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Figure. Anterior views of paralarvae of Megalocranchia fisheri. Photographs by R. Young.
About This Page
University of Hawaii, Honolulu, HI, USA
National Museum of Natural History, Washington, D. C. , USA
Katharina M. Mangold (1922-2003)
Laboratoire Arago, Banyuls-Sur-Mer, France
Page copyright © 2001 , , and Katharina M. Mangold (1922-2003)
Page: Tree of Life
Cephalopod Eye: Position and Size
Authored by
Richard E. Young, Michael Vecchione, and Katharina M. Mangold (1922-2003).
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