68 On a ncio Family of Crustacea IsopoJa. 



infero-anterior an<;le ; from below its front margin on the 

 median line there projects a snjall process which is separated 

 bj a fissure from tlie acute ridge of the upper lip. On its 

 ]iosterior margin the median line of the cephalon is received 

 into a deep indentation of the first segment of mesosome, and 

 it is distinctly divided into two articulations by a transverse 

 tissure. 



The mesosome is nearly two thirds the length of the whole 

 body ; the first segment has no separate coxal plate ; the 

 plates of the second to the fourth segments are short ; on the 

 fifth to the seventh they are well developed and acutely 

 produced backwards. 



The first segment of the mesosome is broad and is slightly 

 produced forwards at the sides ; on the median line it is 

 hollowed to iTceive the cephalon, and on its dorsal surface it 

 bears a transverse suture like an imperfect articulation ; its 

 posterior margin is nearly transverse. The second, third, and 

 fourth segments are narrow, subequal in width, and trans- 

 verse; the filth, sixth, and seventh are slightly broader. 



The metasome shows five distinct joints, the first four 

 being very narrow, while the last is produced into a large 

 terminal piece, which is evenly rounded behind. 



The eyes are placed obliquely near the antero-lateral margin 

 of the cephalon ; they are nearly linear in form and contain 

 several hundred facets. 



The inner antennae are small and have a peduncle of three 

 joints, of which the basal is much the stoutest ; the flagellum 

 is 1 -jointed and is nearly as long as the peduncle, and is 

 directed upwards. 



The outer antennge are 23 mm. in length and pediform. 

 They are 5 jointed, and bear a short 1-jointed flagellum, 

 which ends in a tuft of hairs. 



The mandibles have a strong bidentate cutting-edge, 

 bearing a second much shorter lobe on the inner side; the 

 spine-row is short and carries 5 or 6 short curved spines ; the 

 molar tubercle is thick and strong ; in front of the palp the 

 basal portion is produced into a rounded tooth. 



The palp of the maxillipeds is 5-jointed, the terminal joint 

 being lamellate and rounded at the end. 



The legs are strong and are furnished along the lower sides 

 of the merus, ischium, and carpus with thick tufts of hairs. 

 The first three pairs are directed forwards and are thickly 

 fringed on the lower margins of their joints with these harsh 

 hairs ; the dactyla are long, slender, and curved, and end in 

 the usual brown spines, which are furnished with a short 

 spine at their base. The fourth pair of legs are quite short. 



