Erganzungen zur Halacariden-Fauna (Halacaridae, Acari) der Bretagne-Kuste. Zur Gattung Arhodeoporus und Copidognathus. - In several habitats near Roscoff (coast of Bretagne) Arhodeoporits and Copidognathits are the most abundant genera. The genus Arhodeopoms is represented by the two subspecies A . gracilipes gracilipes (TROUESSART) and A . gracilipes minor n. ssp. A. gracilipes gracilipes is found both in the midlittoral and in the sublittoral, A. gracilipes minor in the sublittoral only. Copidognathus often is the dominant genus, in number of species and in specimens. Three species, new to science, are described. C. venustus n. sp. is an arenicolous species living in the lower midlittoral, C. pseudofigeus is found in microcrevices formed by Lithophyllum, C. litbricellits in sediments, especially in the sublittoral.