ON A NEW BRITISH TERRESTRIAL ISOPOD 87 



dorsal face presents a more definite pattern. The antennae, 

 legs, and uropoda, which in T. spinosus are coloured, are in 

 T. stebbingi generally devoid of pigment. 



Occurrence. I discovered this pretty little species recently 

 (Feb. 6, 1907) in a greenhouse in Springburn Public Park, 

 Glasgow, living in company with T. stebbingi, T. pusillus, 

 Brandt, T. roseus (Koch) and HaplopJitlialnms danicus, Budde- 

 Lund. All these species were bearing ova. I have not yet 

 found it outside the greenhouse mentioned above, but as I 

 first met with the closely allied species, T. stebbingi, in the 

 open country, I have no reason to doubt that T. spinosus 

 will yet be discovered in quite open situations. 



I have drawn attention recently in two papers, relating 

 to the distribution of the terrestrial isopods within the Clyde 

 faunal-area, to the fact that my examination of a large 

 number of hothouses throughout the area showed that the 

 members of the Trichoniscida do not seem to have any 

 marked preference for these places, although the food there 

 is both choice and abundant. Evidently the most important 

 and indispensable condition to their existence is a fairly 

 abundant and steady supply of moisture, and where I have 

 met with these species inhabiting greenhouses, this condition 

 of things usually obtained. Many species, however, belong- 

 ing to the Oniscidce, do not seem to be affected in the same 

 manner, e.g. I have found Porcellio scaber, Latr., P. dilatatus, 

 Brandt, Metoponorthus pruinosus (Brandt), and Cylisticus 

 convexus (De Geer), living in hundreds in tomato-houses in 

 widely separated parts of the Clyde faunal-area, where they 

 seemed to enjoy the almost tropical heat which usually prevails. 



The members of the Trichoniscidcs are evidently a hardy 

 race. Bate and Westvvood refer to Kinahan as having found 

 T. vividus (Koch) quite active mid snow. The same remark 

 may be equally well applied to many more members of the 

 family, for I have found during the past winter (i) T. 

 pygniceus, G. O. Sars, and T. roseus living quite actively in a 

 garden at Dullatur, Dumbartonshire, underneath old logs 

 which were covered with snow and ice, and (2) T. pusillus 

 and H. danicus in several places near Lanark, under the bark 

 of fallen trees, where the interstices had become filled up 

 with ice. 



