Neglecting details for the moment, it may be said that the appendage consists of a basal portion (fig. 44, _cxp, bp_), {165} with two terminal divisions (_ip_ to _dp_, and _ex_), which are directed forwards, below the mouth, and a third, lateral appendage (_e, br_), which runs up, beneath the carapace, into the branchial chamber. The latter is the gill, or podobranchia, attached to this limb, and it is something not represented in the abdominal limbs. But, with regard to the rest of the maxillipede, it is obvious that the basal portion (_cxp, bp_) represents the protopodite, and the two terminal divisions the endopodite and the exopodite respectively. It has been observed that, in the abdominal appendages, the extent to which segmentation occurs in homologous parts varies indefinitely; an endopodite, for example, may be a continuous plate, or may be subdivided into many joints. In the maxillipede, the basal portion is divided into two joints; and, as in the abdominal limb, the first, or that which articulates with the thorax, is termed the _coxopodite_ (_cxp_), while the second is the _basipodite_ (_bp_). The stout, leg-like endopodite appears to be the direct continuation of the basipodite; while the much more narrow and slender exopodite articulates with its outer side. The exopodite (_ex_) is by no means unlike one of the exopodites of the abdominal limbs, consisting as it does of an undivided base and a many-jointed terminal filament. The endopodite, on the contrary, is strong and massive, and is divided into five joints, named, from that nearest to the base onwards, _ischiopodite_ (_ip_), _meropodite_ (_mp_), _carpopodite_ (_cp_), _propodite_ (_pp_), and _dactylopodite_ (_dp_). {166} [Illustration: FIG. 45.—_Astacus fluviatilis._—A, the first; B, the second maxillipede of the left side (× 3). _cxp_, coxopodite; _bp_, basipodite; _e, br_, podobranchia; _ep_, epipodite; _en_, endopodite; _ex_, exopodite; _ip_, ischiopodite; _mp_, meropodite; _cp_, carpopodite; _pp_, propodite; _dp_, dactylopodite.]