( 21 ) 



Body smooth, elliptical ; median plate arched above, scarcely eiir- 

 passing frontal line. Terminal ring ot' abdomen narrow (coxa) obsolete), 

 triangular : apex truncate. False feet of last pair : basis nearly com- 

 pletely concealed, bilobed ; internal lobe much shorter than external ; 

 a raised transverse ridge on inferior face. Ischium flattened, somewhat 

 triangular, wider below than above. Secondary appendage trigonal, 

 broader below than above, compressed, hairy at the end. Second joint 

 of extc^mal antenna) lobed. 



Colour : dark steel-gray, almost black ; steel-gray blotched with 

 patches and spots of whitish-yellow and red browns. 



Habit : rolls itself into a ball. 



Habitat : dry places under stones, decaying timber, and amidst 

 herbage. 



Biitribniion : Ireland generally. England^— London, £ent. 



Family.— 0NISCIDJ2. 



Genus. — Oniscus {Linn.). 



1. — Oniscus 7nuranu8 (Cuvier). 



Synonyms : 0. asellus (Zinnwus, and Auct.). 



Body oval, shining, covered with smooth granules ; lateral lobes of 

 head large, inclined backwards; frontal line somewhat emarginate ; ter- 

 minal ring of abdomen elongate, triangular, convex above ; coxae ter- 

 minating as acute angle ; coxae of fifth concealing origin of accessory 

 appendage. Accessory appendage nearly equalling ischium in length. 

 Second joint of external antennae lobed internally. 



Colour: general ground light-gray or bluish, with blotches and 

 patches of yellow, generally lineally aiTanged; a salmon-coloured variety 

 with dark patches occasionally met near sea. 



Habits : semi-rolls, and feigns death. 



Habitat : under decayed vegetable and animal matter, as well in 

 the dryest as wettest localities. Common near sea. 



Localities : Ireland — east coast generally. England — Kent, London, 

 &c. Appears to be common everywhere, but the species have not been 

 distinguished. 



2. — Oniseus fo88or {II. Schueffer, D. C*rus., Cah. 22, n. 22). 



Synonyms : Oniscus mmcorum {Lerehoullety p. 29). I cannot speak 

 of the other synonyms given by the author, as he has confounded it with 

 Philoscia muscorum. P. tteniola {Koch)^ given by him as a synonym, 

 is figured as a true Porcellio by Schoeffer. The figure of O.fMwr is very 

 characteristic. 



Body oval, covered with numerous rough granulations, which give 

 it a powdered appearance; head convex; lateral lobes moderate, rounded; 

 frontal line produced into a triangular lobe which belongs to head, not 

 to antennal ring ; terminal ring and other characters as 0, muranmy 

 than which the whole animal is much smaller. 



