272 PBOCEEDINGS OF SOCIETIES. 



2. Peduncle irregularly quadrilateral, much broader than long, outer 

 side produced, articulated by lower margin beneath exterior angle of 

 posterior border of the last ring ; entire peduncle almost covered by the 

 ring. Accessory lobe triangular, springing from base of peduncle, 

 scarcely half length of peduncle. Ischium irregularly quadrilateral, 

 base much narrower than apex, which is transverse ; inner side pro- 

 duced at apex, borders hairy. Accessory appendage nearly twice length 

 of ischium ; base rounded, narrow ; apex flattened, club-shaped, hairy 

 and scabrous (Armadillium, Armadillo (?). To this neighbours, probably, 

 Sphaerillo and Diploexochus). Plate XXI., Figs. 12, 13. 



3. Peduncle triangular, much longer than broad, articulating border 

 notched at outer angle, outer margin produced into lobe at base, apical 

 angle well marked, apex half breadth of base, articulated to exterior 

 angle of last ring beneath. Accessory lobe distinct, quadrilateral, about 

 third length of peduncle, arising from articulating margin, completely 

 covered by last abdominal ring. Ischium compressed, acuminate, tri- 

 gonal, lobed on inner side, hairy. Accessory appendage curved, tri- 

 gonal at apex, lobed at base, terminating in filament, two-thirds con- 

 cealed beneath terminal ring, two-thirds length of ischium (Porcellio, 

 Oniscus (which has accessory lobe nearly obsolete), Platyarthus, pro- 

 bably). Plate XX., Pig. 11. 



4. Peduncle quadrilateral, transverse, twice as broad as long, superior 

 articulating border produced into an angle, articulated to lateral border 

 of last abdominal ring. Accessory lobe distinct, nearly attaining apex 

 of peduncle, unconcealed by last ring. Ischium — base flattened, apex 

 acuminate, bi- articulate, hairy, and spined along edges. Accessory 

 appendage falciform, hairy, apex blunt, three-fourths of length of 

 ischium (Philoscia). 



5. Peduncle somewhat triangular, as long as broad, superior border 

 terminating internally in an angle, articulated in a notch of the posterior 

 linear border of the last ring, which passes back below coxa of fifth 

 ring. Exterior margin produced into a triangular lobe. Accessory 

 lobe triangular, distinct, nearly attaining apex of peduncle, uncon- 

 cealed. Ischium subulate, somewhat trigonal at base, terminating in 

 a long filament, smooth. Accessory appendage curved, needle-shaped, 

 smooth, nearly equal in length to ischium (Philougria, Itea (?), and 

 probably also Trichoniscus). 



6. Peduncle quinquangular, oblong, superior border narrow, articu- 

 lated in a distinct notch at the posterior margin of ring ; apex truncate; 

 exterior angle acute ; lateral lobe obsolete. Ischium elongated, trigo- 

 nal, rough, hairy. Accessory appendage rounded, subulate, slightly 

 larger than ischium, terminating in a filament (Ligia). 



Besides these there are several intermediate forms, as Ligidium, in 

 which the accessory lobe far exceeds apex of the peduncle — Actsecia 

 {Dana), in which the external angle of apex is produced into a lobe, so 

 that the ischium appears to be lateral ; but sufficient has been said 

 on the subject. 



The whole of these appendages are capable of reproduction, and it 



