Title La segmentation des appendices chez les Acariens. - The legs of the Acarida present primary and secondary articulations. The primary articulations have their own tendons; the last-mentioned tendons are lacking in secondary articulations. There are three main types of primary articulations: monovalent, bivalent, and rotatary. The terminology of the segments is based here on their sequence and on their articulations. The same criteria can be applied to palp and chelicera. In this way a general survey can be attained comparing the segmentation of the appendages of the mites (cf. table 2).