2S The Irish Naturalist. 



Metoponorthus clngendus, Kin. (fig. n). 



Porcellio cingendus, Kin. 



Metoponorthus simplex, B.-L. 



The narrow segments of the tail distinguish this species and the next 

 from those of the genus Porcellio, In this respect they resemble the 

 species of Tric/ioniscus, but the tail is never so long as in the latter, and 

 the structure of the antennae also is different. The colour of this 

 species is rather striking, being of a steel blue with red or yellowish spots. 

 It runs with great rapidity, and never attempts to roll itself into a Iball. 

 One of the most salient features is the transverse raised line on the 

 anterior portion of each body-segment. 



It has not been taken in England, but in the mountainous districts of 

 Dublin, Wicklow, and Cork, and also on the coast of Kerry, and on the 

 Aran Islands, it is common. 



General Distribution.— France (2). 



Metoponorthus prulnosus, Brandt (fig. 12). 



Porcellio pru inosus, Ki n . 



The segments of the tail are rather wider than in the last species, and 

 in this respect M. pruinosus approaches the Porcellios, but is still suffi- 

 ciently distinguished from them. The surface of the body is more rough 

 and granular than in the preceding one, and the general body-colour is 

 of a uniform reddish-brown, often dotted with white spots. 



I cannot agree with Prof. Kinahan that it is common in Ireland ; it 

 certainly is quite absent from the mountainous districts, and has only 

 been taken in the neighbourhood of Dublin. It often buries itself in 

 the ground. 



General Distribution. — S. B. England only (1), Banff in Scot- 

 land (9), chiefly S. and W. Europe, but also in the East; N. and S. America, 

 N. Africa, Sumatra and Madagascar (2.) 



Platyarthrus HoffmansegrgM, Brandt (fig. 13.) 



I have already mentioned the fact that this species inhabits ants' nests, 

 and is devoid of eyes. It is perfectly white in colour. Moreover, the 

 short flattened antennae and the small size distinguish it at once from all 

 other Irish Wood-lice. The body-surface is strongly granulated. 



The species is new to Ireland. I discovered it first at Leixlip, County 

 Dublin, and since then at Iyismore, County Waterford, and Glengariff, 

 County Cork. 



General Distribution. — S. England (1), Banff, Scotland (9), C. and 

 W. Europe (2). 



Onlscus asellus, Iy. (fig. 14.) 



Oniscus ?nurarius, Cuvier. 



O.fossor, Kin. 



Of all the Irish Wood-lice this is by far the commonest. It was formerly 

 used in medicine, and was supposed to cure consumption and other 

 diseases. The general colour is of a light grey, but it varies from that to 

 light brown and dark grey, and it is marked with patches of yellowish 

 white, especially along the margins of the body-segments. The body- 

 surface is glossy, and furnished with raised tubercles. The three articula- 

 tions in the flagelluni of the outer antennae distinguish it at once from 

 any of the species of Porcellio. 



It occurs in damp as well as in dry situations, especially under bark of 

 fallen trees and under stones everywhere. I recently submitted speci- 

 mens of Prof. Kinahan's Oniscus fossor to Prof. Budde-Lund, who failed to 

 recognize any specific distinction between it and this species. The young 

 of 0. asellus appear always to be less glossy than adults, and of a more 

 uniformly grey colour. 



General Distribution. — Throughout England and Scotland (1), 

 almost throughout Europe, Azores, and North America (2.) 



