Définition : Living in the fluid medium (water or air) but unable to maintain their position or distribution independently of the movement of the water/air mass (adapted from Lincoln et al., 1998).
Définition : A landform consisting of loose rock particles such as sand, gravel, shingle, pebbles, cobble, or even shell fragments along the shoreline of a body of water.
Définition : A group of hydrous aluminium phyllosilicate (phyllosilicates being a subgroup of silicate minerals) minerals (see clay minerals), that are typically less than 2micrometres in diameter. Clay consists of a variety of phyllosilicate minerals rich in silicon and aluminium oxides and hydroxides which include variable amounts of structural water.
Définition : A structural quality inhering in a bearer by virtue of the bearer's being thicker or more closely packed together; pressed tightly together.
Définition : A compound eye with no separation between the crystalline-cone layer and the retinula, each rhabdom receiving light only from its own corneal lens.
Définition : A compound eye with no separation between the crystalline-cone layer and the retinula, each rhabdom receiving light only from its own corneal lens.
Définition : superposition compound eyes where each ommatidium is equipped with a set of plane mirrors, aligned at right angles, forming a square. Rays entering the eye at an oblique angle encounter two surfaces of each mirror box rather than one surface. In this case, the pair of mirrors at right angles acts as a corner reflector. Corner reflectors reflect an incoming ray through 180 degrees, irrespective of the ray’s original direction. This ensures that all parallel rays reach the same focal point and means that the eye as a whole has no single axis, which allows the eye to operate over a wide angle.
