THE LIGIIDJE 421 



In the five pairs of pleopods the outer branch is opercular, 

 the inner branchial, but sexual in the first two pairs of the 

 male. The uropods are produced beyond the apex of the 

 pleon. The young are said to quit the mother with only 

 six pairs of trunk-feet. The family contains seven or 

 eight genera. 



Ligia, Fabricius, 1798, has a multiarticulate flagellum 

 to the second antennas, the maxillipeds with a small 

 rounded epipod, and the ' palp ' four- to five-jointed. The 

 uropods have two equal, stiliform, often filiform, branches. 

 Ligia oceanica (Linn.) is found on rocky shores of Great 

 Britain and in many parts of northern and western 

 Europe. The uropods are not unlike those of Asellas 

 aquaticus. It attains a length of more than an inch, 

 without including uropods and antennae. In Ligia, exotica, 

 Roux, the second antennas are longer than the animal, the 

 fiagellum having from twenty-seven to forty-one joints. 

 Ligia cursor, Dana, from Valparaiso, hints by its specific 

 name at what is rather a character of the genus, rapidity 

 of running. Von Siebold says that in Japan on rocky 

 shores at ebb-tide in summer the Ligias are sometimes so 

 abundant that the fishermen sweep them with brooms 

 into pots, to be used for bait. Budde-Lund in 1885 de- 

 scribes in all twelve species from the shores of various parts 

 of the world, and gives the names of five others. Ligia 

 dilatata, Perty, he renames in 1879, Stymphalus dilatatus, 

 and he includes Dana's Styloniscus, with its three species, 

 in this family. 



Ligidium, Brandt, 1833, has a multiarticulate flagellum 

 to the second antennas, the ' palp ' of the maxillipeds 

 conical, five-jointed, the stem of the uropods obliquely 

 produced on the inner side, and the inner branch tipped 

 with two hairs. Five species have been described. Ligi- 

 dium liypnomm (Cuvier, 1792) has had several names. 

 In England it has hitherto only been recorded from the 

 borders of Surrey and Sussex. Budde-Lund supposes 

 that the Bavarian species Zia paludicola, Koch, and Zia 

 melanocephala, Koch, belong to this genus. 



Trichoniscus, Brandt, 1833, has the flagellum of the 



