The external morphology of the gill of Patella caerulea L. (Mollusca: Gastropoda)

Gross morphology of the gill was studied using a scanning electron microscope (SEM) in order to associate it with its function in genus Patella. Secondary gills consisted of a single layer of gill folds, which appear mostly as triangular leafl ets in scanning electron micrographs. The lamellae showed a prominent thickening on the free margin and horizontal swellings, which bear a series of ciliary structures on the frontal surface, as well as disperse bunches. They differed from the discocilia and, because chemoreception has been attributed to them in the absence of an osphradium, they are thought to contribute to the primary respiratory role of the gills. These morphological characteristics are to be researched further, both in natural and experimental specimens of this genus.