Yew D T, Li W W
Department of Anatomy, Faculty of Medicine, Chinese University of Hong Kong, Shatin, New Territories.
Anat Anz. 1987;164(5):331-43.
The eyes of 2 species of fishes with dorsal eyes Uranoscopus oligolepis and Paralichthyes olivaceus were studied. In the Uranoscopus, ciliary projections were not conspicuous and in the Paralichthyes, the projections were small. 3 types of photoreceptors were observed in both species--rods, single cones and twin cones. In both species, the number of twin cones increased towards the central retinae and in the Paralichthyes, the single cones also increased in number. The rods were lowest in the central region. In the orbit, both species displayed complex solid bones. For example, the lateral border of the orbit was a complex formed by the lacrimal, suborbital, postorbital and parietal. In the Paralichthyes, the lateral orbital border was actually continuous with the orbital and parietal bones and the border was not distinct. The formation of fused plates would serve to restrict eye movement as well as to resist deep sea pressure acting from above.
对两种具有背眼的鱼类——少鳞瞻星鱼和褐牙鲆的眼睛进行了研究。在瞻星鱼中，睫状突起不明显，而在褐牙鲆中，突起较小。在这两种鱼类中均观察到3种光感受器——视杆细胞、单锥体细胞和双锥体细胞。在这两种鱼类中，双锥体细胞的数量向视网膜中央增加，并且在褐牙鲆中，单锥体细胞的数量也增加。视杆细胞在中央区域最少。在眼眶中，这两种鱼类均显示出复杂的实心骨骼。例如，眼眶的外侧边界是由泪骨、眶下骨、眶后骨和顶骨形成的复合体。在褐牙鲆中，眼眶外侧边界实际上与眶骨和顶骨相连，边界不明显。融合板的形成有助于限制眼球运动以及抵抗来自上方的深海压力。
