180
THE BIOLOGY OF EUPHAUSIIDS
which enable filtering of food to take place and suggests
function of the exopodites is to bring water from a greater
the animal to the mouthparts.
that the main
region around
A euphausiid, which has access to the sea bottom, can feed on
bottom material. This it does by two methods. I n the first (Fig. 64) it
approaches the bottom a t an angle very near the vertical and beats its
pleopods so that a water current is produced which disturbs and raises
the surface layers of the mud into suspension ; the animal then moves
FIQ. 63. Respiratory currents produced by the pleopods only,
the exopodites of the thoracic limbs
remaining inactive.