183 



rather large, sub-discontiguous, 1st pair securiform in shape, posterior corners of 

 this and the succeeding pairs acuminate. Metasome scarcely occupying y 4 of the 

 length of the body, epimeral plates of 3rd to 5th segments prominent, recurved; 

 last segment nearly as long as it is broad at the base, outer part conically pro- 

 duced and plane above. Antennae slender, though scarcely attaining half the 

 length of the body, flagellum shorter than the last peduncular joint, and having 

 its proximal articulation scarcely more than half as long as the distal one. Legs 

 about as in P. Rathkei. Opercular plates of all pleopoda provided with air- 

 cavities. Uropoda of moderate size, resembling those in P. Rathkei. Colour of 

 dorsal face more or less dark grey, with a regular row of whitish patches on 

 each side, at the base of the side-plates of mesosome, and an assemblage of less 

 distinct wavy stripes on each side of the median line; edges of the side-plates 

 tinged with light yellow. Length of adult male 11 mm. 



Remarks. For the identification of this interesting species, not yet found 

 in any of the Scandinavian countries, I am indebted to Mr. Budde-Lund, who 

 kindly sent me for comparison some specimens of this form from the central 

 part of Europe. It is nearest allied to P. Rathkei, but easily distinguishable from 

 it by the very prominent cephalic lobes, of which the middle one (frontal lobe) 

 especially exhibits a rather peculiar appearance from its regular semicircular form. 

 Occurrence. I have hitherto only succeeded in finding 2 specimens of 

 this form, a female and a male. They were taken this summer in the neigh- 

 bourhood of Christiania (Bygd0) beneath loose bark, and were at first confounded 

 with P. Rathkei, to which species it bears a rather close resemblance. 



Distribution. Central part of Europe: Upper Pfaltz, Bohemia, Saxony. 

 ia, Tyrol. 



Gen. 5. MetOpOnOFthUS, B.-Lund, 1879. 



Syn: Porcellionides, Miers. 



Generic Characters. Body oblong, subdepressed, with very thin integu- 

 ments. Cephalon with the lateral lobes very small, frontal lobe obsolete. Side- 

 plates of mesosome but very slightly prominent. Metasome abruptly contracted, 

 with the epimeral plates of 3rd to 5th segments sub-appressed ; last segment 

 comparatively short, triangular. Eyes well developed, lateral. Antennula? very 

 small, with the last joint quite short. Antennae slender and elongated, flagellum 

 biarticulate. Oral parts nearly exactly as in Porce.llio. Legs slender, and greatly 



