EXPLANATION OF PLATES 



PLATE I. 



Fig. 1, la — Potamon fluviatile var. gedi-osianum, S , nat. size. 



Fig. 2, 2a, 26 — Potamon atkinsonianum var. emphyseteum, S , nat. size. 



Fig. 3, 3a — Potamon hifarium, S , nat. size. 



Fig. 4, 4'/, 46 — Potamon hispidum, S , nat. size. 



PLATE IL 



Fig. 5, 5a, 5b— Potamon turgidulum, c? , x 2. 

 Fig. 6, 6a, 66 — Potamon tumidulum, <? , x 2. 

 Fig. 7, la — Potamon simulum, ? , nat. size. 



PLATE IIL 



Fig. 8, 8a — Potamon pruinusum, S , X li. 



Fig. 9, 9a — Potamon turgidulimaniis, (J , x 2. 



Fig. 10, 10a, 106 — Potamon (Poiamiscus) annandalii, S , nat. size. 



Fig. 11, 11a, 116 — Potamon (Geotelphusa) adiatretum, cJ, x 2. 



PLATE IV. 



Fig. 12, 12a — Potamon (Acanthotetphusa)fungosum, <$ , nat. size. 



Fig. 13, 13a, 136, 13c — Potamnn {Acanthotelphiisa) crenuUferum, S > nat. size. 



Fig. 14, 14a — Potamon (Acanthotelphusa) calvum, $ , nat. size. 



Fig. 15 — Paratelphusa trilohata, 9 , x 1|. 



Fig. 16, 16«, 166 — Paratelphusa llamf.ordi, S , nat. size. 



PLATE V. 



Fig. 17, 17rt, 176 — Paratelphusa grayi, c? , x 2. 



Fig. 18 — Paratelphusa {Barytelphusa) lamcllifrons, ?, nat. size. 



Fig. 19, 19a, Idb^Paratclphnsa {Barytelphusa) edentula, S , nat. size. 



Fig. 20, 20a, 20b— Paratelphusa (Barytelphusa) nupma, 6 , nat. size. 



Fig. 21, 21a, 216 — Paratelphusa (Barytelphusa) pulvinata, 6 , nat. size. 



13S 



