The frontal cells are situated at the apex of the gill filament. The surface of these cells is covered by many individual cilia. These bands of frontal cilia run the length of the gill filament to the food groove. The frontal ciliary tracts serve to conduct captured food particles to the food groove, and from thence to the labial palps and the mouth.
Image of frontal cilia below.
1. An SEM of the gill of Polymesoda caroliniana showing the frontal cilia running from left to right in the image. The structures that resemble horse tails are the frontal cirri typical of this species. Also note that they are all on the same side of each gill filament. Approx. magnification of the original photo – 1.03kx.
