Body slender-cylindrical, with the lateral processes wide apart, each furnished with a dentiform projection at the tip. Cephalon hardly longer than the one succeeding it, frontal spines close together, the collar having a slight sinus in the middle on the dorsal side. Chelifores and palps absent. Abdomen oblong-oval, truncate at the posterior end and on either side armed with a short spine.
Ocular tubercle exactly in the middle of the cephalon, prominent, acuminate, the four eyes comparatively small, closer to the base than to the tip of the tubercle. Proboscis more than half as long as, and hardly slenderer than, the rest of the body, slightly expanded in the middle.
Ovigerous legs in male only, about half the length of the body, with seven segments. The second segment largest, the 5th segment larger than either of the two preceding or succeeding it, sharply curved; last segment triangular, scarcely half as long as the preceding, with two short spines on the inner margin.
Ambulatory legs nearly three times the length of the body, armed with scattered spines, unequal in length; 2nd coxal segment longer than the two other taken together; femur twice as long as the coxal section and terminating outwards in a conical process, armed with two spines of different length. Tibia 1 shorter than tibia 2, the latter about as long as the femur; tarsus obliquely rounded; propodus about four times longer than broad, terminating outwards in a sharp corner, inner margin furnished at the base with five spines, the two outmost placed side by side, terminal claw more than half as long as the propodus; auxiliary claws less than half as long as the main claws.
Body translucent, with the intestine and its lateral expansions of a green colour. Length of the body in females, taken from the tip of the proboscis to the posterior end of the abdomen up to 4 mm; the extent between the points of the ambulatory legs reaching 23 mm. The males are generally somewhat smaller.
Occurs in the littoral zone and in the sublittoral, down to 12 m.
Norway to the Mediterranean.
This species is Endeis laevis Grube, 1871 of King (1974). Endeis spinosa of King (1974) is included in Endeis charybdaea (Dohrn, 1881). Endeis charybdaea is found off the south-west coast of Britain. It differs from Endeis spinosa by longer auxiliary claws and numerous spines around the mouth.