60 MOLLUSCA. 
A variety is sometimes found, particularly in a stream near 
Folkstone, in Kent, finely striated longitudinally. Montagu 
says 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 strize 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, pl. XII, f. 3, 5, and 7—First Ed., 
pl. 36, f. 3, 5, and 7. 
Ancylus lacustris, Miiller, Verm., I, p. 199; Drapernaud, 
p- 47, pl. 2, f. 25, 26, 27; Pfeiffer, p. 109, pl. 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, pl. 10, f. 1265 
Thompson, Ann. and Mag. Nat. Hist., VI, p. 475 Patella 
lacustris, Linné, Syst. Nat., p. 1260, No. 769; Pennant, Brit. 
Zool., IV, p. 142; Montagu, Test. Brit., p. 484; Donovan, 
Brit. Sh., pl. 150; Brown, Wernerian Mem., II, p. 533; Ib., 
Ency. Brit., VI, p. 466; Patella oblonga, Maton and Rackett, 
Linn. Tr., VIII, p. 233; Lightfoot, Phil. Trans, LXXVI, p. 
168, pl. 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- 
Length a little more than a quarter of an inch; breadth 
about half its length. 
white. 
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, Potamogeton; in the drains 
of the bog meadows, near Belfast; the Lagan canal; in a pond 
at Moira, County of Down; and various other situations. 
Famity I[V.—CatyprTRaAcka. 
Branchie 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.—CaLyprr@a.—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 
septem, 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. 
[GasTEROPODA 
1. CatypTrma Sinenss, pl. XX, f.16 and 18.—First Ed., 
pl. 37, f. 16 and 18. 
Calyptreaa Sinense, Lamarck, VI, pt. 2nd, p. 22; Brown, 
Conch. Text Book, p. 90, pl. 14, f. 19; Calyptra@a chinensis, 
Fleming, p. 362; Patella chinensis, Linné, p. 1257; Montagu, 
p: 489; Patella Sinensis, Brown, Ency. Brit., VI, p. 464; 
Patella albida, Donovan, pl. 129. 
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, flat, thin, transversely 
oblique, extending from nearly the margins to the centre, on 
one side, and forms the external subyolution. 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. PiEopsis uNGARICA, pl. XX, f. 19, 20.—First Ed., pl. 
37, f. 19, 20. 
Pileopsis ungarica, Lamarck, VI, pt. 2nd, p. 17; Brown, 
Conch. Text Book, p. 100, pl. 14, f. 31; Patella ungarica, 
Martini, I, pl. 12, f. 107, 108; Pennant, IV, p. 149, pl. 90, f. 
147; Patella ungarica, Montagu, p. 486; Donovan, I, pl. 21, 
f. 1; Brown, Ency. Brit., 6th Ed., VI, p. 465; Ib., 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. 
