UV radiation blocking compounds in the eye of the cuttlefish Sepia officinalis.

Abstract

scribed as the respiratory current (1), shows that when the book gills are active, the lateral slits entrain dye ventrally and dorsally. In both cases, dye passes the flabella. The flabella are therefore situated in the respiratory current where they can monitor chemical stimuli drawn in from a distance. However, when the last pair of legs, known as the pusher legs, are active and the book gills are inactive, these slits can serve as expulsion sites. The book gills were also able to entrain dye placed within 2 cm lateral to the opisthosoma. Limulus spends time with its prosoma burrowed in the sand (4); as a result, we hypothesize that the flabella allow the animal to sense chemical signals in its environment while partially buried. Both currents described above are expelled posteriorly under the telson when the book gills are active. Currents can be reversed and dye forced out the flare, however, when an animal flaps its opisthosoma and telson forward.