Die Ästheten mit intrapigmentärem Schalenauge vonChiton marmoratus L. (Mollusca, Placophora)

The structure of the intrapigmented aesthetes and the properiostracum layer in Callochiton achatinus (Mollusca: Polyplacophora)

“…The ultrastructure of the aesthetes of three species of British chiton have been described previous to this study, namely, Lepidochitona cinereus (Linnaeus) (Boyle, 1974), Acanthochitona fascicularis (Linnaeus, 1767) (Fischer, 1979) and Tonicella marmorea (Baxter et al, 1987). The general conclusions that have been drawn from these studies, and others on foreign species (Haas & Kriesten, 1978;Fischer, 1988), are that the aesthetes have both sensory and secretory functions. The possible sensory functions have received much more consideration, with frequent analogies made with the structure of other invertebrate photoreceptors (Haas & Kriesten, 1978;Fischer, , 1979.…”

“…There are a number of descriptions of the ultrastructure of aesthetes (Boyle, 1974;Fischer, , 1979Fischer, , 1988Fischer & Renner, 1978;H a a s & Kriesten, 1978;Baxter, Jones & Sturrock, 1987), but only that of Haas & Kriesten (1978) describes the intrapigmented aesthetes.…”

“…Various suggestions as to the functions of the aesthetes have been presented, based on ultrastructure observations. In species both with (Haas & Kriesten, 1978) and without (Fischer & Renner, 1978;Fischer, 1988) intrapigmentary bodies, photoreceptor cells have been described. Baxter, Jones & Sturrock (1987), however, found no photoreceptor cells within the aesthetes of Tonicella marmorea (Fabricius) and proposed an alternative, periostracum secretion role.…”

THE CANAL SYSTEM IN SCLERITES OF LOWER CAMBRIANSINOSACHITES(HALKIERIIDAE: SACHITIDA): SIGNIFICANCE FOR THE MOLLUSCAN AFFINITIES OF THE SACHITIDS

“…B is modified from Haas 1981. C is reproduced from Haas and Kriesten 1978 and D is reproduced Fischer et al . 1980 both from Zoomorphology, with kind permission of Springer Science and Business Media.…”

Biology of the Integument

“…Such photo receptors occur in the pallial tentacle eyes of the bivalves Pecten maximus and Cardium edule, while the eyes in the outer shell of chitons, and the paired cephalic eyes of most gastropods and cephalopods possess photoreceptors which are primarily rhabdomal (Barber et al 1967, Eakin and Brandenburger 1967, Barber and Wright 1969a, Boyle 1969, Haas and Kriesten 1978. The ciliary photoreceptors usually possess 75-200 modified cilia which are flattened out to form a membrane array for the attachment of a photosensitive pigment.…”