162 



Occurrence. — According to Mr. BudcloLimcl, this form was many years 

 ago observed here in Norway by Prof. Lilljeborg, who found it at Molde. 

 Some few specimens are, moreover, preserved in our University Museum from 

 earlier times, having been collected by the late Dr. A. Boeck in the neighbourhood 

 of Christiania, and I have also recently received this form from Trondhjem 

 through the kindness of Conservator Storm. I have myself found it very 

 frequently in many places around Christiania, as also at Drobak and Laurvig, 

 beneath moist leaves, stones and pieces of wood, especially in very shady places. 

 A certain degree of moisture seems to be indispensable to its existence, and there- 

 fore in dry places fully exposed to the sunshine, it is never met with. When 

 disturbed, it runs about with great agility to conceal' itself, and is thus only 

 with difficulty got hold off, and being very fragile, it is easily damaged when 

 caught. It is very curious that among the numerous specimens collected, I have 

 failed to detect any male specimen. Perhaps the male sexual characters in this 

 species are so very inconspicuous as to escape attention. 



Distribution. — Sweden, Denmark, Germany, France, Britain, Spain, Al- 

 geria, North America. 



2. Trichoniseus pygmaeus, G. 0. Sars, n. sp. 



(PI. LXXII, fig. 2.) 



Specific Characters. — Body rather narrow, oblong, fully 3 times as long as it 

 is broad, dorsal face rather convex and rough, the roughness arising from numerous 

 small tubercles arranged in transversal rows. Cephalon rounded, with the lateral 

 lobes extremely minute, front rather arcuate. Lateral parts of the segments of meso- 

 some edged with small appressed spikes; those of the 3 posterior segments, as 

 in T. pusillus, more prominent than the preceeding ones, and terminating in re- 

 curved conical points. Metasome rather narrow, and of a similar structure to 

 that in T. pusillus; last segment with the terminal expansion gradually tapering, 

 and narrowly truncated at the tip, carrying 2 rather long apical hairs. Anten- 

 nula?. with the last joint scarcely longer than the 2nd, and only provided with 3 

 sensory filaments. AntennaB comparatively less slender than in T. pusillus, flagel- 

 lum scarcely attaining the length of the last peduncular joint, and composed of 

 only 3 articulations. Legs comparatively shorter than in the type species, but 

 otherwise of a similar structure. Inner ramus of 1st pair of pleopoda in male 

 greatly produced, with the terminal joint narrow knife-shaped; that of 2nd pair 

 Particulate, proximal joint very short, distal joint long and slender, styliform. 

 Uropoda rather short, with the rami nearly equal, and but little longer than the 



