CONCHO LOGY. 



77 



compressed at the upper outer margin, where it joins 

 the body; lip white; pillar lip furnished with two 

 teeth, and deep within the mouth are three or four 

 prominent ridges; length nearly three quarters of an inch. 

 Test. Brit. tab. 1 1 . fig. 4. 

 Animal light brown, paler beneath, tentacula and 

 eyes resembling the preceding species. 



14. Biplicata. Shell with twelve or thirteen taper 

 striated spires ; mouth compressed at the upper part, 

 and slightly at the extremity ; lips thick, white, re- 

 flected; margin connected all round; pillar lip pro- 

 minent and detached, furnished with two white ap- 

 proximating teeth-like laminae; length three quarters 

 of an inch. 



15. Labiata. Shell light brown, opake, taper, with 

 nine spires, wrought with strong and regular stria? the 

 whole length of the shell; volutions flat; mouth sub- 

 orbicular with a sinus at the upper end, and furnished 

 with two teeth-like laminae on the inner lip ; margin 

 very broad, thick, and white ; pillar lip a little detach- 

 ed from the body whorl ; length five eighths of an inch. 



Test. Brit. tab. 11. fig. 6. 

 Found by Mr Swainson in ozier grounds at Batter- 

 sea, Surry. 



16. Vertigo. Shell oval, opake, brown, with five 

 faintly striated spires ; apex obtuse ; aperture sub-trian- 

 gular, sub-marginated, indented, usually furnished with 

 three white teeth, two on the columella, and one on 

 the exterior lip opposite ; length half a line. 



Test. Brit. tab. 12. fig. 6. 

 Tentacula two, with eyes at their tips. Found by 

 Mr Boys and Mr Montagu on old ivy walls. 



Genus XV. Lvmn^a. 



Shell ovate conical, mouth entire, longitudinally ob- 

 long, the right lip joined to the left at the base and folding 

 back on the pillar. 



Obs. The genus Helix of Linnaeus is unquestionably 

 a confused one. The discoide species of that genus we 

 have already considered under the genus Planorbis, and 

 the turreted species from the present genus, which was 

 constituted by Lamarck, and of which Latreille gives the 

 following definition : " Coquille oblongue, presque turri- 

 culee ; I'ouverture entiere, plus longue que large ; partie 

 inferieure du bord droit remontant en rentrant dans I'ou- 

 verture, etformant sur la columelle un pli tres oblique." 



1. Stagnalis. Shell thin, translucent, with six or se- 

 ven spires ; the first very large, the others small and 

 tapering to a fine point ; slightly wrinkled longitudi- 

 nally ; outer lip thin, pillar lip thickened. Length one 

 inch and three quarters ; breadth one inch. 



Brit. Zool. tab. 86. fig. 136. Helix. 

 Test. Brit. tab. 16. fig. 8. 

 This species is the largest of the British fresh water 

 univalves. It inhabits slow running rivers and stag- 

 nant waters. 



2. Fragilis. Shell thin, translucent, horn-coloured ; 

 slender in the superior volutions ; whorls little raised. 



Test. Brit. tab. 16. fig. 7. 

 Found by Mr Montagu in the canal between Chip- 

 penham and Laycock in Wiltshire. 



3. Palustris. Shell horn-coloured, with six spires ta- 

 pering to a sharp point ; whorls slightly wrinkled longi- 

 tudinally, sometimes marked with irregular transverse 

 ridges ; length an inch, breadth three eighths. 



Test. Brit. tab. 16. fig. 10. 

 Brit. Shells, tab. 175. fig. 1, 2. 

 In ditches and swamps in England. It has been ob- 



served in Duddingstone Loch, near Edinburgh, by Dr Univalves. 

 Leach. "V™"* 



4. Fossaria. Shell thin, horn-coloured, tapering, with Fossaria, 

 five or six spires ; whorls rounded, divided by a well- 

 defined separating line ; length three eighths of an inch; 

 breadth about one third of its length. 



Test. Brit. tab. 16. fig. 9- 

 Animal dusky ; tentacula two, somewhat compressed, 

 short ; eyes on the head at the base of the tentacula. 

 In shallow pools exposed to the sun and in muddy 

 ditches. Common in England and Scotland. 



5. Putris. Shell with four spires, the first very Putris, 

 large, the others small, apex fine pointed; mouth 

 large oval, three fourths of the length of the shell ; usual- 

 ly covered with a dusky brown epidermis ; length one 

 inch, breadth five-eighths. 



Brit. Zool. tab. 86. fig. 137. 

 Test. Brit. tab. 16. fig. 3. Helix peregra. 

 The animal is an aquatic species of a yellowish co- 

 lour, with two broad flat pyramidal tentacula, eyes at 

 the base of the tentacula beneath. Common in Britain 

 in almost every ditch. 



6. Auricu/aria. Shell thin, sub-pellucid, with four Auricula- 

 spires, the first extremely large occupying almost the na > 

 whole of the shell ; apex pointed ; body whorl longitu- 

 dinally wrinkled ; outer lip much extended, thin, and 

 sub-reflected; length about an inch, breadth three 

 quarters of an inch. 



Brit. Zool. tab. 86. fig. 138. Helix auricularis. 

 Brit. Shells, tab. 51. fig. 1. 

 Test. Brit. tab. 16. fig. 2. 

 Tentacula of the animal broad, flat, conic, speckled 

 with brighter yellow. Found in stagnant pools in Eng- 

 land ; common in Scotland. Somewhat rare. 



The variety of this shell termed Helix limosa, Test. 

 Brit. tab. 16, fig. 1, is only the young of this spe- 

 cies. The first volution is less ventricose, and thinner, 

 and the mouth not so patidous ; but it has no character 

 to entitle it to be considered as distinct. The Helix 

 limosa of Linnaeus is essentially different. 



7. Succinea. Shell very thin, pellucid, glossy, red- Succiaea, 

 dish-yellow, with three spires, the first very large, 

 wrinkled longitudinally ; mouth oval, occupying two- 

 thirds of the shell ; outer lip submembranaceous ; pil- 

 lar lip slightly thickened ; length three-quarters of an 



inch. 



Test. Brit. tab. 16, fig. 4, Helix putris. 

 The animal of this shell has four tentacula. This 

 species resides upon the leaves and stalks of subaquatic 

 plants. It is a very common species in Britain. 



8. Lutea. "Shell sub-oval, sub-pellucid, with about Lutea_, 

 three whorls, the first very large ; mouth oval, expand- 

 ed ; length nearly half an inch ; breadth rather more 



than a quarter. 



Test. Brit. tab. 16, fig. 6. 

 It is exceedingly doubtful, whether this is a land or 

 a sea shell. Mr Montagu has found it on the open part 

 of the coast of South Devon. 



9. Detrita. Shell conic, sub-pellucid, with six whorls, Detrita, 

 not much elevated, but a little rounded, and separated 



by a well defined line ; colour white, glossy ; a little 

 wrinkled longitudinally, and commonly marked with 

 one ferruginous band round the middle of the body ; 

 mouth oval ; length three quarters of an inch ; breadth 

 three-eighths. 



Test. Brit. tab. 11, fig. 1. 

 Found by Mr Bryer in a pool near Weymouth, and 

 in a stream near Dorchester. . . 



10. Vivipara. Shell with six ventricose spires, sepa- Vivipara, 

 rated by a deep depressed line ; shape sub-conic, sud- 



