FAMILY : ONCHIDIIDAE
Onchidium daemelii Semper 1882

The animal shown here is from the Tweed River. It is very common on mud flats behind the mangroves in the Cobaki Broadwater. Also occurs in the Brunswick River.

An unexpected characteristic of certain species of Onchidiidae is that in addition to an eye at the end of each tentacle, there are numerous "eyes" on the back which is rough looking and covered with coarse papillae. The eyes, in groups of two, three or four, are situated on top of these papillae. The papillae themselves are retractile, so that the tip can be let down and in. This retraction can be observed when one touches a papilla, but it does not seem to happen unless actual contact is made. In other words evidence that the eyes can "see" or are sensitive to shadow is difficult to obtain.

W.J.Dakin. 'Australian Seashores'

 

© All images Copyright 2007 Denis Riek. All rights reserved.