CONCHOLOGY. 



CO 



Univalve?, when old it becomes conical. Found on old shells in 

 V T""~"' Zetland. 



Lucidu", 11. Lvcidus. Shell white, gloss}', pellucid, irregu- 



lar, whorls two or three, sometimes lateral, and often 

 projecting upwards and unconnected, diameter half a 

 line. 



Test. Brit. p. 506. 

 Animal red, with plumose tentacula of a pale colour, 

 and two brown spots on the head. Frequent on co- 

 rallines, especially Serlulai-ia abietina, 

 Iteversus. 12. Reversus. Shell white, rugose, subcylindric, 



subspiral, tapering to a small point ; diameter at the 

 larger end one-tenth of an inch. 



Test. Brit. p. 508. 

 Found on Pecten opercularis, on the coast of Devon, 

 by Mr Montague. 



Genus IX. Planorbis. 



IX. Pla- Shell simple spiral depressed, spires lateral, mouth 



mokbis. oblique. 



Obs. The species of this genus were included among 

 the Helices by Linna?us. The continental naturalists 

 have long ago separated them, and constituted the pre- 

 sent genus. They possess many characters in common. 

 They are all of a horn colour, subpellucid, and the 

 mouth is placed obliquely to the direction of the whirls. 

 They inhabit fresh water ditches, ponds, and rivers. 

 The base of these shells is known by its being more 

 sunk in than the upper side, and, from the gradual di- 

 minution of the whorls towards the centre, forming a 

 funnel-shaped cavity. 

 Corneus, 1. Corneus. Shell brownish coloured, subpellucid, 



whorls four, rounded, separated by a deep spiral line, 

 apex much depressed, forming a cavity, underside a lit- 

 tle concave, wrinkled transversely ; mouth sublimated ; 

 diameter an inch and quarter. 



Brit. Zool. tab. 83. fig. 26. H. corneus. 

 Brit. Shells, tab. 89. fig. 1. 

 Common in England, in ditches, and old drains. 

 Complana- 2. Complanatus. Shell with five whorls gradually 

 nis. decreasing to the centre, rounded, separated by a deep 



spiral line, wrinkled transversely, margin carinated, 

 terminating at the inferior angle of the mouth, diame- 

 ter five-eighths of an inch. 



Test. Bfil. tab. 25. fig. 4. Helix complanatus. 

 Brit. Zool, tab. 82. fig. 123. H. planorbis. 

 Animal dusky, with two long slender setaceous ten- 

 tacula of the same colour, opake, dark in the middle. 

 Common in ditches, in England and near Edinburgh. 

 Carinatus. 3. Carinatus. Shell a little glossy, whorls four, 

 wrinkled across, outer one broad, sloping to a carina 

 on both sides, which enters the mouth, the inner whirls 

 decrease suddenly to the centre, where is a small cavi- 

 ty, base nearly flat, diameter about three-fourths of an 

 inch. 



Lin. Sijst. Helix planorbis. 

 Test. Brit. tab. 25. fig. 1. 

 Lift. Tra?is. vol. viii. tab. 5. fig. 14. 

 The animal differs from the preceding species in the 

 tentacula, being somewhat longer, pellucid, yellow, 

 and not darker in the middle. In ditches and ponds, 

 in England frequent, and near Edinburgh. 

 Vortox, 4. Vortex. Shell with six or seven whirls, above 



concave, beneath flat, even, marked with a fine sepa- 

 rating line, exterior whorl subcarinated at the lower 

 edge, diameter scarcely half an inch. 



Test. Brit. tab. 25. fig. 3. 

 Brit, Zool. tab. 83. fig. 124. 

 Brit. Shells, tab. 75. 



Anima dusky, with two long filiform tentacula, and Univalves, 

 two black eyes placed at their base. Common in Eng- "•"•"V""""' 

 land, in ponds and ditches. . 



5. Spirorbis. Shell with six whorls exactly lateral, Spirorbis, 

 round, both sides flat; diameter three-tenths of an inch. 



Test. Brit. tab. 25. fig. 2. 

 In rivers and ditches, England, and at Livingstone, 

 West-Lothian. 



6. Conlorlus. Shell with five or six whorls, the out- Contorts, 

 er one rounded ; above even, the whirls divided by a 

 separating line, With a cavity in the Centre ; beneath 



with a large central cavity; mouth bent, embracing the 

 body whorl ; diameter about one-tenth of an inch. 

 Test. Brit. tab. 25. fig. 6. 

 Brit. Shells, tab. 9.9. 

 Animal dusky, with two long filiform tentacula, with 

 the eyes placed at their base. In ditches in England, 

 rather a local species, and near Edinburgh and Cupar. 



7. Albus. Shell with four lateral compressed whorls, Albu=, 

 the outer one subcarinated ; above the apex a little de- 

 pressed; beneath it is furnished with a cavity; striated 

 transversely and longitudinally ; mouth clasping the bo- 

 dy whorl ; diameter a quarter of an inch. 



Test. Brit. tab. 25. fig. 7- 

 Pult. Dorset, tab. 19. fig. 18. 

 Animal light coloured, with two long filiform tenta- 

 cula, with two eyes at their base on the top of the head. 

 Frequent in rivers and ponds in England ; found also 

 at Dunbar, by Mr Laskey. 



8. Cristatus. Shell with three or four rounded whirls cristar.u% 

 striated transversely; above, the apex is little sunk, be- 

 neath there is a cavity; aperture orbicular; diameter one- 

 tenth of an inch. 



Test. Min. Rar. tab. 1. fig. 18. 

 Tett. Brit, vignette 1. fig. 7, 8. 

 Animal dusky, with four tentacula, and a plumose 

 appendage, the body lobated in front. In England 

 rare. 



9- Fontanus. Shell smooth, glossy, nearly equal on Fontaine, 

 both sides, above, subdepressed, the cavity beneath, large 

 and exhibiting the volutions; whorls four, the outer one 

 subcarinated; diameter two- tenths. 



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

 Animal light chesnut, with two filiform tentacula, 

 head long. Frequent in England, has been found at 

 Cupar. 



10. Nautileus. Shell with four whorls, ribbed across, NautiJeus. 

 with a subspinous carina, above flat, beneath with a 

 large cavity; diameter one-eighth of an inch. 



Test. Min. Rar. tab. 1. fig. 20, 21. 

 Test. Brit. tab. 25. fig. 5. 

 Animal of a pale colour, tentacula, two setaceous ; 

 eyes on the head at the base of the tentacula. In ponds 

 and ditches, in England frequent. 



SECT. II. STULIDIA. 



The shells included in this Section are all of them Stulidla. 

 more or less spiral and revolve round a central pillar, or 

 columella, as it is sometimes called. The genera of 

 this Section admit of distribution into three families, 

 Turreted, Globose, and Convoluted. 



Family I. TURRETED. 



The shells of this family have then' whorls much pro- 

 duced above, and are of a lengthened conical form. 

 The length of the shell usually exceeding greatly the 

 breadth of it. This family includes six genera, Bucci- 

 num, Murex, Strombus, Turbo, Odostomia, and Lym- 

 naea. These genera admit of distribution into two tribes, 

 4- 



