86 ANNALS OF SCOTTISH NATURAL HISTORY 



Cephalon with front obtusely rounded, lateral lobes moder- 

 ately produced and bearing one or two small spines on the 

 outer edge. Lateral parts of the segments of mesosome 

 edged with small appressed spines, the three posterior 

 segments having the corners recurved and acuminate. 

 Metasome occupies about one-fourth of the length of body, 

 the terminal expansion of the last segment being obtusely 

 rounded at the tip and armed with from two to five 

 triangularly-shaped spines. Antennulse with the last joint 

 longer than the second and bearing from four to six sensory 

 filaments. Antennae about one-third the length of body, 

 spinulose, and the flagellum composed of three articulations. 

 Eyes consist of three visual elements embedded in dark 

 pigment. Left mandible with two, right with one, penicil 

 behind the cutting part. Last pair of legs in both sexes of 

 the same structure, the last joint having on the outer edge 

 three or four short but fairly prominent spines. Inner ramus 

 of first pair of pleopoda of male not greatly produced, the 

 tip of the last joint reaching to the middle of the distal joint 

 of second pair ; the last joint of very delicate structure, 

 needle-shaped and about twice the length of first. Inner 

 ramus of second pair biarticulate, the last joint about three 

 times the length of first, abruptly contracted at about two- 

 thirds towards the distal end and terminating in a spear-like 

 point. Uropoda with the outer ramus about twice the length 

 of basal part, the inner ramus being narrower and shorter. 

 Colour dark reddish brown, marbled with white. Length of 

 adult female 3.5 mm. 



Remarks. This species bears some resemblance to 

 Trichoniscus stebbingi, Patience, in the general form of the 

 body ; in the type of coloration ; in the structure of the 

 first pair of pleopoda of the male, and in the shape of the 

 last segment of the metasome. The telson, however, in 

 T. spinosus is more obtusely rounded at the tip than in the 

 above-named species, and in this respect connects T. stebbingi 

 with the other British species of Trickoniscus, where the tip 

 of the last segment of the metasome is truncate. Again, the 

 last joint of the inner ramus of the first pair of pleopoda of 

 the male is slightly longer and comparatively more slender 

 than in T. stebbingi, while the colour arrangement on the 



