British Terrestrial Isopod. 281 



discernible on the dorsal face of the female. Length of adult 

 male and female specimens about 3 mm. 



Remarlcs. — 'J'liree sjiecimens of this species (one male and 

 two females) were sent to me for examination by my friend 

 Mr. R. S. Bagnall, F.E.S., Winlaton-on-Tyne, and, so far as 

 I have been able to ascertain, it does not seem to have 

 been hitherto described. It is at once distinguished from all 

 the other British species of Trickoniscus by its consj)icuonsly 

 linear form, ap})roaching nearer to T. pi/gmceus, G. 0. Sars, 

 in this respect than any otiier member of the genus. It 

 offers some further points of resemblance to the just-named 

 species, notably in the form and structure of the first and 

 second pairs of pleopoda of the male. T\\& inner ramus of 

 the tir>t pair in both species shows a close resemblance ; the 

 proximal p;irt of the outer plate, however, is more broadly 

 exp;inded in T. linearis; while the distal joint of the inner 

 ramus of the second pair appears to be more flexible than 

 that found in T. pijgmceus. It differs obviously, however, 

 from that species in the structure of the eje, having only 

 one visual element — in this respect resembling not only 

 T.roseus (Koch), but also Trichoniscoides albidus (B.-Lund), 

 Ihiplophthalmus danicus, B.-Lund, and //. mengii (Zaddach) ; 

 while the dorsal face is very much more strongly tubercu- 

 lated, and the tip of the last segment of the rnetasome is 

 rounded, whereas in T. pygmccus it is truncate. T. linearis 

 agrees in the form of the telson with T. atebhingi, Patience, 

 and T. fpinosus, Patience. 



Occurrence. — Mr. Bagnall found three specimens in Kew 

 Gardens, London, December 3rd, 1'..07, in company with 

 J/aplo/dithalmus danicus, Budde-Lund, under flower-pots, in 

 a moderately cool greenhouse. In these fl )\ver-pots, among 

 the roots of several plants, T. stehbingi was also found. 

 Mr. Bagnall informs me that its movements are slower than 

 any other species of the genus, resembling rather the move- 

 ments of IJaplop/iihalnius, and, in consequence of this, was 

 regarded as belonging to that genus until examined under a 

 microscope. 



The genus Trichoniscxis is readil}' distinguished from 

 Uaplophtlialnnis by the abiuptly contracted metasome, the 

 epinieral plates of the two anterior segments not bL'iiig 

 concealed. These latter in llopU phthulmus are small and 

 concealed by the lateral part ot the last segment of the 

 mesosome, while the three })Osterior segments are broadly 

 expanded. The sculpture of the tlorsal tace in this genus is 

 also somewhat different, having more or less distinct longi- 



