158 



Remarks. This genus, established by Brandt, is chiefly distinguished from 

 Ligia, by the abruptly contracted metasome, the less rudimentary state of the an- 

 tennulffi, and the peculiar structure of the uropoda. The genus Zla of Koch is 

 identical with the present genus. Several species have been described, amounting, 

 according to Mr. Budde-Lund, to 8 in all. Only one species belongs to the 

 Scandinavian fauna, and it will be described below. 



Ligidium hypnorum (Cuv.). 



(PI. LXXI.) 



Oniscus liypnornm, Gtivier, Journ. d'hist. nat. Vol. II, p. 19, pi. 26, figs. 3 5. 



Syn : Oniscus agilis, Persoon 

 Ligia liypnorum, Bosc. 

 Zia agilis, Koch 

 ,. Ligidium Personii, Zadclach 

 Zia Soundersii, Stebbing 

 Ligidium agile, Norman. 



e Characters. Body oblong oval, greatest width not attaining half 

 the length, dorsal face rather convex, and perfectly smooth and shining. Cephalon 

 of moderate size, and evenly rounded in front, dorsal face transversely grooved 

 behind the eyes. Lateral parts of the 3 anterior segments of mesosome but 

 slightly prominent; those of the 4 posterior segments somewhat larger, and ter- 

 minating behind in obtuse points. Metasome scarcely exceeding in length 1 / s of 

 the mesosome, and much narrower, with the epimeral plates small and apprcssed; 

 last segment obtusely rounded at the tip, with a slight angle on each side. Eyes 

 very large, oval, extending down Ihe sides of the cephalon. Antennulse with the 

 1st joint rather thick, 2nd longer but much narrower, both armed at the tip in- 

 side with 3 rather long diverging spines, last joint very small, narrow cylindric. 

 Antennae rather slender, though not nearly attaining half the length of the body, 

 flagellum somewhat shorter than the peduncle, and composed of about 11 arti- 

 culations, the last tipped with a dense bunch of delicate hair-like bristles. Legs 

 armed with scattered slender spines, propodal joint very narrow and elongated. 

 dactvlus simple. Inner plate of 1st pair of pleopoda in male slightly produced 

 at the tip, and provided with 4 apical bristles. Uropoda scarcely exceeding half 

 the length of the metasome, inner projection of the basal part occupying 

 about halt' its length, outer ramus gradually tapering distally and carrying 

 "ii the tip 3 short bristles, inner ramus very narrow, linear, not extending 

 to the tip of the outer, apical bristles nearly as long as the ramus. Colour 

 of dorsal face light fuscous, variegated with irregular dark patches, which on each 

 side, at the base of the lateral plates of mesosome, form a nearly continuous 

 longitudinal band. Length of adult female 9 mm. 



