Comparative aspects of habenulae in some species of Chondrohycthes and Ostehycthes

Diencephalic habenular nuclei of several species of Chondrohycthes and Ostehycthes fishes were investigated in order to ascertain their asymmetry. Raja asterias, Squalus acanthias, Mustels mustelus, Scyliorhinus canicula and Scyllium stellare show the left habenula larger than the right, as occurs in the elasmobranchs till now investigated. Among the six species of teleostean fishes we studied, the habenulae of Liza aurata, Anguilla anguilla and Trisopterus minutus are symmetrical, while in Lepidorhombus boscii, Platichthys flesus and Solea vulgaris the habenulae are slightly asymmetrical. This finding might suggest a relation, to be better investigated, among bentic life and habenular asymmetry in teleostean.