A HISTORY OF HERTFORDSHIRE Helicella virgata (Da C.) itala (Linn.) caperata (Mont.) cantiana (Mont.) Hygromia fusca (Mont.). Gallows Hill, Haileybury granulata (Aid.) hispida (Linn.) rufescens (Penn.) Acantbinula aculeata (Moll.). Hitchin ; Swiss Cottage, Cassiobury Park ; Hoddesdon Fields Vallonia pulchella (Mull.) Helicigona lapicida (Linn.). Hitchin ; Tring ; Sandridge ; Gallows Hill, Haileybury arbustorum (Linn.) Helix aspersa, Mtill. pomatia, Linn. Hitchin ; St. Albans ; Harpenden ; Marford Bridge and Waterend, Wheathampstead ; Gallows Hill, Haileybury nemoralis, Linn. kortensit, Milll. Buliminus montanus (Drap.). Hitchin abscurus (Mull.) Cochlicopa lubrica (Mtill.) Azeca tridens (Pult.). Hitchin ; Sandridge Ctecilianella acicula (Mull.) Pupa secale, Drap. Beech woods at Aldbury, Tring cylindracea (Da C.) mtucorum (Linn.) Sphyradium edentulum (Drap.). Swiss Cottage Woods, Cassiobury Park Vertigo antivertigo (Drap.). Hitchin pygmeea (Drap.). Hitchin ; Ware ; Rye House moulinsiana (Dup.). Near Hitchin ; near Broxbourne Balea perversa (Linn.). Hitchin Clausilia laminata (Mont.) bidentata (Strom.) biplicata (Mont.) rolphii, Gray. Gallows Hill, Hailey- bury Succinea putris (Linn.). In addition to the type a variety, which has been described as a separate species, under the name of S. virescens, has been found at St. Albans. e/egans, Risso. Hemel Hempstead ; Gor- hambury, St. Albans ; Ware b. BASOMMATOPHORA Carychium minimum, Mtill. Hitchin ; Swiss Cottage, Cassiobury Park ; Haileybury Anychii jfaviatiia, Mull. Velletia lacustris (Linn.). Sopwell, St. Albans ; Hoddesdon Fields Limntsa auricularia (Linn.) pereger (Mtill.) palustris (Mull.) truncatula (Mull.) stagnalis (Linn.) Planorbis corneus (Linn.) a/bus, Mull. g/aber, JefF. St. Margaret's nautileus (Linn.) carinatus, Mull. marginatus, Drap. vortex (Linn.) spirorbis, Mull. contortus (Linn.) fontanus (Lightf.) lineatus (Walker). Ware Physa fontinalis (Linn.) hypnorum (Linn.). Hitchin II. PROSOBRANCHIATA Bythinia tentaculata (Linn.) leachii (Shepp.). Hitchin ; Ware V'mipara vivipara (Linn.) Vafoata piscina/is (Mull.) cristata, Mull. Hitchin ; Ware Pomatias elegans (Mtill.). Hitchin ; Ashridge Park, Tring ; Gorhambury Park, St. Albans ; near Wheathampstead ; Brocket Park, Welwyn ; Gallows Hill, Haileybury Neritina JJuviatilis (Linn.). River Lea B. PELECYPODA Drelssensia polymorpha (Pall.) Unio pictorum (Linn.) Anodonta cygn&a (Linn.) Spheerium rivicola (Leach). Rickmansworth ; River Lea corneum (Linn.) 'lacustre (Mull.). Hitchin ; Rickmans- worth ; Ware Pisidium amnicum (Mflll.) pusillum (Gmel.). Hitchin ; Watford ; Ware nitidum, Jenyns. Watford ; Ware fontinale (Drap.). Sopwell, St. Albans ; Rickmansworth ; Ware milium (Held.) 82