PLATE I. (continnrd). 



PLATE H. (cuntinmd). 



14 Limnaea palustris 



stagnalis 



ir. corva (L.nieliii) 

 obesa (Tjiylor) 

 elongata (Muq.) 

 , conica (-leftVeys) 

 minor ( TjivIui) 

 tincta (Jeflreys) 

 lacunosa (Zgl-) 

 fasciata (Nelson) 

 , roseolabiata (Jeti'. ) 

 , albida (Nelson) 

 decoUatum (JeHreys) 

 s-.yy. acuta (JellVey.-s) 

 , ampla (Havtinami) 

 , reflexa (Nelson) 

 magna (Colh.). 

 albida (.leirn-y ) 

 ir. frag-ilis (LiiiMi') 

 bottnica (CMessiii) 

 vni-. lacustris (Studer) 

 var. labiata Jettreys 

 var. variegata (Ha/ay) 

 var. albida (JeHVeys) 

 111. sinistrorsum (JeHVey.s; 

 scalariforme 



Larger, more tumid, dark purple. 



Very tumid. 



Si)ire more produced. 



Conical, suture deep, with an umbilical cleft. 



Smaller, 8 mm. x 4i mm. 



.Shorter and broader, mouth purplish. 



Witli row.s of lualleationa. 



With three spiral dark bands on body whorl. 



With rose-coloured rib. 



■White. 



Spire truncate. 



Smaller, oblong, mouth narrower. 



Aperture extending beyond apex. 



Outer lip much rertected. 



Larger, month narrower. 



W I lite. 



Smallei'. thi 



slender. 



Smaller, dark, suture deep. 



Spire short, body whorl large. 



Outer lip enlarged. 



With variegated white markings 



AVhite. 



Sinistral. 



Whorls disconnected. 



Amphipepli 

 Limnsea truncatula 



•21 Physa fontinalis 



Aplexa hypnorui 

 Ancylus fluviatil: 



26 Velletia lacustris 



27 Neritina fluviatilis 



glutinosa V. mucronata (Jed'.) 

 - var. albida (Williams) 



ventricosa ( Mocj . ) 

 s (Jein-eys) 

 . microstoma (Drouet) 

 . albida (Nelson) 

 scalariforme (JeHVeys) 

 elongata (JeHVeys) 

 r. inflata (Moq.) 

 ■. curta (JeilVeys) 

 . oblonga (JeHVeys) 

 ■. albina (JetlVcys) 

 ■ar. rubra (Tryon) 

 ar. capuloides (Jan.) 

 ■. gibbosa (li'iuiguignat) 

 ■. stricta (Motel) 

 -. albida (JetlVeys) 

 ir. compressa (Jeffreys) 

 ■. moquiniana (liourg. ) 

 ■- albida (Jeltreys) 

 i-av. cerina (Colb. ) 

 ■. trifasciata (Colb.) 

 r. undulata (Colb.) 

 r. nigrescens (Colb.) 



Spire more produced. 



White. 



Tumid, spire short. 



Larger, tapering spire. 



Mouth contracted. 



Wliite. 



Whorls disunited. 



Spire produced. 



Mucli larger, more ventricose. 



Spire very short. 



Spire produced. 



White. 



Dark reddisli. 



Larger, ape.M near tlie centre. 



Small, with apex overhanging posterior i 



Much elevated, sides compressed. 



White. 



Broader and flatter. 



Elevated, compressed at sides. 



White. 



Leu 



i-coloured. 



AVith three spiral dark bands, 

 Transversely banded. 

 Uniformly dark coloured. 



Paludestrina ventrosa vur. ovata t.U 

 — — var. elongata (JelV 



jenkinsi 

 stagnali 



Valvata cristata 

 — piscinalis 



;^.3 Bythu 



leachii 



37 Vivipara vivipara 



— contecta 

 Succinea putris 



oblonga 



pellucid 



carinata iSmith) 

 ■. tumida (Marshall) 

 barleei (JeHVeys) 

 octona (Limie) 

 albida (JeHVeys) 

 alba (Uuwe) 

 r. depressa (C. Pfr.) 



— var. antiqua (Snwerby) 



— var. acuminata (.leHVeys) 



— var. pusilla (Muller) 



— 111. sinistrorsum (Jeftreys) 

 tentaculata \'ai. producta (Menke) 



— var. ventricosa iMenke) 

 ^ var. excavata (JeHVeys) 



— var. albida (Kimmer) 

 elongata (JeHVeys) 



. albida (Kiniiner). 

 . efasciata d'ickeviug) 

 . atro-purpurea (Lloyd) 

 . albida iXel>. .S: Tayl) 

 sinistrorsum 

 r. virescens (.leHVeys) 

 . subglobosa iJeHVeys) 

 . stagnalis (Cjussies) 

 ■. solidula (JeHVeys) 

 •. vitrea (Mmi.) 

 ■. albida (.M.irch) 

 r. alba (Wiight) 

 sinistrorsum (Taylor) 

 V. longiscata (Morel) 

 \ar. pfeifferi (Ktissiu.) 

 var. virescens (Morel) 

 var. ochracea (lietla) 

 var. albida (Taylor) 

 m. sinistrorsum (liaudon) 



Spire shorter, wl 

 Spire longer. 

 White, trauspart 

 Keiiled. 

 More tumid. 



spiiidle-sliaped, mouth s.ii 

 , thimier, suture deeper. 



elegans 



Smaller, 



Smalle 



Whitish. 



White. 



Flatter, umbilicus larger. 



Spire more raised. 



Spire more produced, apex sharper. 



Smaller, strijv stronger, whorls 4.^. 



Sinistral. 



Larger, spire produced. 



Shorter, more tumid. 



Suture deepei", wliorls more roundei 



White. 



Spire produced. 



White. 



Without bands. 



Dark purple all over. 



White. 



Sinistral. 



Without bands. 



Shorter, broader, more solid. 



Smaller, straighter front margin. 



Thicker and deeper coloured. 



Thinner and paler. 



White. 



White. 



Sinistral. 



Shell longer, moutli compressed. 



Shorter, not so much drawn out. 



Thin, greenish yellow. 



Smaller, thicker, spire longer, mou 



Wliite. 



Sinistral. 



