Ml 



MOLLUSCA. 



[Gasteropoda 



A variety is sometimes found, particularly in a stream near 

 Folkstone, in Kent, finely striated longitudinally. Montagu 

 savs this variety is so strongly striated, that it was by some 

 considered a distinct species. He adds, "these were of an 

 inferior size, and covered with a dusky epidermis, differing in 

 nothing but the stria? being more conspicuous." 



Common in most rivers and streams in Great Britain and 

 Ireland, adhering to stones at the bottom. 



Section II. — Animals dextral. 



2. Ancylus lacustris, pi. XII, f. 3, 5, and 7. — First Ed., 

 pi. 36, f. 3, 5, and 7- 



Ancijlus lacustris, Miiller, Verm., IT, p. 199; Drapemaud, 

 p. 17. pi. 2, f. 25, 26, 27; Pfeiffer, p. 109, pi. 4, f.46; Lamarck, 

 VI, pt. 2nd, p. 27 ; Fleming, Brit. An., p. 280 ; Alder, Mag. 

 Zool.and Bot., II, p. 116; Turton, Man., p. 141, pi. 10, f. 126; 

 Thompson, Ann. and Mag. Nat. Hist., VI, p. 47; Patella 

 lacustris, Linne, Syst. Nat., p. 1260, No. 769; Pennant, Brit. 

 Zool., IV, p. 142; Montagu, Test. Brit., p. 484; Donovan, 

 Brit. Sh., pi. 150; Brown, Wernerian Mem., II, p. 533; lb., 

 Ency. Brit., VI, p. 466 ; Patella oblonga, Maton and Rackett, 

 Linn. Tr., VIII, p. 233 ; Lightfoot, Phil. Trans., LXXVI, p. 

 168, pi. 3, f. 1. 



Shell conical, and of a much elongated, oval form, com- 

 pressed on the sides, thin, smooth, but not glossy, or slightly 

 wrinkled, nearly membranaceous, subpellucid, of a pale horn- 

 colour, covered with a yellowish-green epidermis; vertex small, 

 acute, placed somewhat posteriorly, a little reflected, obliquely 

 inclining towards the narrower end; aperture oblong-oval; 

 margin membranaceous; inside smooth, glossy, and of a bluish- 

 white. Length a little more than a quarter of an inch; breadth 

 about half its length. 



Found in lakes and still ditches, in many situations in Great 

 Britain and Ireland, adhering to aquatic plants. We may par- 

 ticularise the Stour, Dorsetshire ; the Thames, near Windsor ; 

 Windermere ; and in a pool near the Eccles station, on the 

 Liverpool and Manchester Railway ; Duddingston Loch, near 

 Edinburgh ; and in Ireland, I met with it in a millrace, near 

 Naas; Thompson gives as localities, Potamogcton; in the drains 

 of the bog meadows, near Belfast; the Lagan canal; in a pond 

 at Moira, County of Down ; and various other situations. 



Family IV. — Calyptracea. 



Branchiae of the animal situate in a dorsal cavity near the 

 neck, and included in the cavity, or projecting beyond it; shell 

 invariably external. 



Genus 9 Calyptrjea Lamarck. 



Shell conical; vertex subcentral, imperforate, and acute; base 

 or aperture orbicular, or nearly so, its margins sharp and entire; 

 internal cavity provided with a lateral, internal appendage, or 

 scplem, which varies much in form in different species. Seve- 

 ral species provided with a strongly marked muscular impression, 

 situate immediately above the fold of the inner lip ; in other 

 species it is placed on the outside of the inner lip, but never 

 within it. 



1. Calyptr;ea Sinense, pi. XX, f. 16 and 18. — First Ed., 

 pi. 37, f. 16 and 18. 



Caltjptrtva Sinense, Lamarck, VI, pt. 2nd, p. 22; Brown, 

 Conch. Text Book, p. 90, pi. 14, f. 19; Cah/ptraa chinensis, 

 Fleming, p. 362; Patella chinensis, Linne, p. 1257; Montagu, 

 p. 489 ; Patella Sinensis, Brown, Ency. Brit., VI, p. 464 ; 

 Patella albida, Donovan, pi. 1 29. 



Shell thin, subpellucid, subconic, much depressed, of a pale 

 yellowish-brown colour, or cream-white, rounded at the margin ; 

 vertex nearly central, terminating in a small, concentrically 

 subspiral tip ; external surface undulated, or wrinkled, in some 

 specimens, and a little rough, with concave scale-like projec- 

 tions; aperture nearly circular; inside very glossy, smooth, and 

 white, in some instances of a very pale pink colour, and pro- 

 vided with a subspiral internal columella, or transverse sub- 

 septem, or columellar projection, broad, Hat, thin, transversely 

 oblique, extending from nearly the margins to the centre, on 

 one side, and forms the external subvolution. Height some- 

 what more than half an inch ; diameter nearly an inch. 



Found at Penryn, in Cornwall ; Helford Harbour ; and on 

 the West coast of Ireland ; but is a rare British species. 



Genus 10 Pileopsis. — Lamarck. 



Shell obliquely conical, posteriorly recurved, with an unci- 

 neate spiral apex, the volutions separated, and rolled inwards ; 

 aperture large, ovate ; anterior margin shortest, the posterior 

 one large and rounded ; inside with elongated, transverse, 

 muscular impressions, situated under the posterior margin ; 

 external surface clothed with a thick, hard, somewhat pilous 

 epidermis. 



1. Pileopsis ungarica, pi. XX, f. 19, 20 First Ed., pi. 



37, f. 19, 20. 



Pileopsis ungarica, Lamarck, VI, pt. 2nd, p. 17; Brown, 

 Conch. Text Book, p. 100, pi. 14, f. 31 ; Patella ungarica, 

 Martini, I, pi. 12, f. 107, 108; Pennant, IV, p. 149, pi. 90, f. 

 147; Patella ungarica, Montagu, p. 486; Donovan, I, pi. 21, 

 f. 1 ; Brown, Ency. Brit., 6th Ed., VI, p. 465 ; lb., Wernerian 

 Mem., II, p. 533 ; Capulus hungaricus, Fleming, p. 363 ; 

 Forbes, p. 33. 



Shell subconic, with a greatly reflected vertex, terminating in 

 a spiral wreath underneath, consisting of two or three small 

 volutions, which are not inclined to either side, except the 

 apicial one ; it is a subpellucid, rather thin shell, strongly 

 striated longitudinally, with strong concentric wrinkles, of a 

 yellowish-white, or flesh-colour, and covered externally with a 

 yellowish-brown, rough, pilous, velvet-like epidermis ; aperture 

 nearly orbicular, with an oblique, internally sloping lip, narrow 

 towards the vertex side, and gradually widening, on both sides, 

 towards the other extremity ; inside extremely smooth and 

 glossy, white, sometimes of the most beautiful rose-colour ; 

 outer lip more or less indented, and crenated, with the epider- 

 mis projecting beyond it, in the form of a silicate border. 



This species is by no means rare on many of the coasts 

 around Great Britain and Ireland. It is very frequently found 

 adhering to oysters and stones brought from the bottom by the 

 dredge. 



