Pack Berf.sford and Foster — The Woodlice of Ireland. 171 



LIGIA. 



Seventeen species of the genus Ligia are known from various parts of the 

 world, but of these one species only inhabits our area. 



We have records of it from every 

 county division which has a coast-line 

 (with the exception of S.E. Gal way, 

 where it no douht exists) and even from 



Ligia oceanica (Linn.). 

 35 



27 

 16 



9 



8 



3 



28 



26 

 17 



15 



10 



7 



5 



35 m 39 



33 36 37 

 32 

 30 

 23 

 19 

 13 

 12 



38 



29 



25 

 24 

 18 

 14 

 11 

 6 



31 

 22 

 21 

 20 



This species literally swarms all round 

 our coasts, wherever rocks or shingle 

 afford it a suitable habitat. 



the shore of Co. Meath, which is almost 

 entirely a stretch of sand. It might 

 almost be called a semi-marine animal, 

 as it is never found more than a few 

 feet above high-tide mark. "We have 

 also found this species a considerable 

 distance up the tidal portion of the 

 Eiver Blackwater in Co. "Waterford 

 and also up the tidal canal almost to 

 the town of Newry in Co. Armagh. 



TKICHONISOUS. 



Of the six species of the genus Trichoniscus known to inhabit England 

 only four have been found in Ireland; but we have one species, T. vividus, 

 which has not so far been taken in England. They may be distinguished 

 from each other as follows : — 



Species. 



A. Single-lens eye. 



(a). Body surface smooth and shining . . vividus. 



(h). Body surface rough and tuberculated. 



(&'). Apex of telson squarely truncated . roseics. 



(¥). Apex of telson rounded . . linearis. 



B. Compound eye of three lenses. 



(a). Body surface covered with strong tubercles . stehlingi. 

 (b). Body surface covered with strong spines 



pointing backwards .... spinosus. 

 (c). Body surface smooth or slightly granulated, 

 (c'). Body surface very smooth, apex of 

 telson concave, outer ramus of 

 uropods nearly twice the length : 



of the basal joint, outer ramus 

 longer than inner , , , jihsUIus. 



