M roa 
——  HÓNE 
Mollusca of Great Britain. 389 
Testa depressa, utrinque planior, subumbilicata, subtis 
perforata, fragilis, diaphana, politissima, ferrugineo- 
cornea aut albida. Anfractus 3—4; ultimo in carinam 
acutiusculam utrinque obliquante. Apertura elongata, 
angulata : peristomio non reflexo, columelle insidente. 
Long. 0.05.— Diam. 0.175. 
Planorbis nitidus. Müll. Verm. 2. p. 163. 
— complanatus. Drap. Hist. des Moll. p. 45. 
t. 2. f. 290—292. 
Helix fontana. Lightf. in Phil. Trans. 76. t. 2. f. 1. 
Mont. Test. Brit. p. 462. t. 6. f. 6. 
On aquatic plants in ditches ; but not very common. 
13. LINEATUS. 
Animal griseo-fuscum. Tentacula filiformia. (Lightf.) 
Testa suprà convexa, subtüs planior, perforata, utrinque 
subumbilicata, | ragilis, | diaphana, politissima, albido- 
lutescens. Anfractus 5—-6 ; ultimo in carinam infe- 
riorem obtusam utrinque obliquante, septis internis 3 
vix 4 albis partito. Apertura elongata, angulata: pe- 
ristomio non reflexo, columellz insidente. 
Long. 0.15.— Diam. 0.275. 
Planorbis nitidus. Drap. Hist. des Moll. p. 46. t. 2. 
f-11-—192.— 
: Helix lineata. Walker Test. Min. Rar. t. 1. Jf 28. 
E eee lacustris. - Lightf. in Phil. Tra 16: 1.1. 
= r F 2 7 
‘ty specimens were re prcoeited to me by Mr. f s. Miller, 
and I believe came from the neighbourhood of London. 
The internal plates seem to stand in the place of the teeth 
or folds which barricade the apertures of mang other Mol- 
^o lusca; 
