296 CRUSTACEA OF NORTHUMBERLAND AND DURHAM 



I put them away, and they thus escaped my memory. I was 

 very interested therefore to find upon re-examination that the 

 species was apparently conspecific with the one just described, 

 or, at least, very closely allied to it." 



When alive P. Patiencei bears a very strong superficial 

 resemblance to the ubiquitous Trichouiscus pusilhis, both in 

 its general appearance and movements. N.D. 



Platyarthrus Hoffmanseggii Brandt. 



1898. Platyarthrus Hoffmanseggi, Sars (G. O.), Crust. 

 Norway, vol. ii., Isopoda, p. 175, pi. Ixxvi., fig. 2. 



1906. Platyaj'thrus Hoffmanseggii, Webb and Sillem, The 

 British Woodlice, p. 30, pi. xii. 



Carley Hill Quarry, near Sunderland (G. S. B.). Two 

 examples with Myrmica 7'tibra at Chopvvell, and several with 

 the same ant at Greatham, near Hartlepool (Bagnall). D. 



PoRCELLio SCABER Latrcille. 



Very common, " Including varieties marmorata and mar- 

 ginata of Brandt and Ratzeburg, the latter variety very rare. 

 Also a large form, bright red in colour, which might be called 

 var. nifa, a single specimen Winlaton, and three examples 

 sent to me by Mr. Donisthorpe, taken in the nest of the red 

 ant Formica sanguinea. A small variety is found in colonies 

 in the busiest parts of the nests of the wood ant Formica rufa 

 at Corbridge-on-Tyne ; it is much smaller than the type, the 

 dorsal surface not so scabrous, cephalic lobe less pointed, and 

 distal joint of the flagellum longer in relation to basal joint j 

 but as the sexual characters, etc., on dissection, entirely agree 

 with P. scaber, it would be better to regard it as a form of that 

 species, most likely produced after several generations of life 

 with the ants ; it might bear the distinguishing name var. 

 Dariuiuiana. On two occasions I have found colonies almost 

 identical with the last living under stones in rock-pools of salt 

 water and entirely submerged ; and when disturbed they merely 

 ran along the bed of the pool to seek shelter under another 

 submerged stone or piece of weed" (Bagnall). N.D. 



