CUUSTACKA. 655 



To this division also belongs Oniscus viridis of SLABBER, Natuurk. Ver- 

 lust. PI. 12, figs. 4, 5, which, according to MILNE EDWARDS, forms a 



distinct genus. 



* 



Arcturus LATE. Feet of first pair short, palpiform. Feet of 

 second, third and fourth pair furnished with long hairs, with last 

 joint plane, elongate. External antennae of the length of body. 



Sp. Arcturus Baffini WESTW., Idotea Baffini SABINE, MILNE EDWARDS Hist, 

 not. des Crust. PI. 31, fig. i; Arcturus longicornis WESTW., GUKRIN 

 Iconoyr., Crust. PL 31, fig. i; in this species the first four pairs of feet 

 stand very remote from the last three. 



OKDER VIII, Amphipoda. 



Eyes sessile. Four antennae, the two middle inserted above the 

 lateral. Mandibles mostly furnished with palps. Two pairs of 

 maxillse and one pair of foot-jaws. Trunk mostly divided into 

 seven distinct segments, bearing seven pairs of feet not cloven into 

 two oars. Membranous vesicles for respiration adhering to the base 

 of some of the feet. 



We unite here, after the idea of KROEYER, the Lcemodipoda of 

 LATREILLE with the order of the Amphipods ; see KROEYER Tids- 

 skrift, iv. 1843, pp. 490495. 



Section I. Lcemodipoda. Posterior part of abdomen or tail 

 short. First segment of trunk conjoined with head, an oblique 

 furrow alone on each side indicating the separation; feet of this 

 segment inserted forwards, beneath the head. Two or three pairs 

 of branchial vesicles in the anterior part of trunk. 



Lcemodipoda from ACUJUOS and Smous; these animals were thus 

 named because they have two feet under the head, as though at the 

 throat. They do not swim, but creep on marine plants and animals 

 in search of food. The posterior part of the body is little developed. 

 In most the feet are wanting in those rings that carry gill- vesicles, 

 and conversely the gill-vesicles are wanting on those rings that have 

 feet. 



Family XXI. Lcemodipoda. (Characters of the section). 



Phalanx I. Gyamea. Body oval, mostly much depressed, with 

 transverse segments. Antennas with four joints, the last slender; 



