7o LAND AND FRESH-WATER SHELLS. 



(a) Shell oval, globular, amber or yellowish-horn coloured, thin, 

 transparent ; whorls three to four, inflated, the last one forming 

 nearly the whole of the shell ; spire slightly produced ; suture 

 rather deep; mouth oval. Mantle partly covering the shell. 

 Length -| inch. Ditches, ponds, and lakes. Very local. 



A. glutinosa.* 1 



ii. Limnaea. Shell oval, thin, transparent; mouth oblong; 

 columella with an oblique plait; non-operculated. Mantle not 

 capable of being reflected over the shell. 



(a) Shell ovate, thin, fragile, pale amber-coloured, glossy, 

 whorls three to four, convex, the body whorl very large; spire 

 sunk within the last whorl; suture shallow; mouth pyriform, 

 large. Length 5^- lines. In a small alpine lake on Cromaglaun 

 Mountain, Killarney, Ireland. Z. involuta. 



(b) Shell oval, last whorl swollen, thin, glossy, yellowish-horn 

 colour ; whorls five, convex, the body-whorl very large ; spire 

 raised and sharp at its apex ; mouth large, oval, more than half 

 the length of the shell. Length ^ to i inch. Stagnant waters 

 and slow running streams. Common. L. peregra?' 2 



(c) Shell globosely ovate, glossy, yellowish-horn coloured, semi- 

 transparent ; whorls four to five, the last one very much swollen 

 and occupying fths of the shell ; spire short, acute ; mouth roundish 

 oval, vastly expanded, oblique. Length i inch. Lakes, ponds, 

 canals, marshes, and sluggish rivers. Moderately local. 



L. auricu lariat 



(d) Shell elongated, ovate, oblong, thin, greyish -white, horn or 

 brown coloured; whorls six to eight, striated in line of growth, 

 the body-whorl occupying nearly f ths the length of the shell ; spire 



31 v. mucronata, not quite so globular, spire more produced. 



32 v. labiosa, smaller, outer lip remarkably expanded and reflected; v. 

 ovata, ampullaceous, glossy, whorls very convex, spire acute and very short, 

 suture deep, aperture obliquely produced, f ths the length of the shell ; v. 

 acuminata, resembling v. ovata but has the spire more produced and the mouth 

 smaller ; v. burnetti, spire exceedingly short, nearly truncate, intorted ; v. 

 nitida, larger, slightly transparent, fauve, coloured ; v. solcmia, ventricose, 

 whorls rounded, spire short, fauve, subtransparent ; v. snccincceformis, shaped 

 like a succinea, whorls four; v. intermedia, rather compiessed towards front 

 margin, thinner, spire more produced, mouth expanded. 



ss v. albida, smaller, thinner, white, spire shorter, striae less distinct; v. 

 reflexa, outer lip much reflected ; v. magna, larger, aperture narrower, outer 



