28 



MOLLUSCA. 



[Trachelipoda 



Valvata cristata, pi. XIV, f. 66, 67 — First Ed., pi. 

 41, f. 66, 67. 



Valvata cristata, Midler, Verm., p. 198; Fleming, Brit. An., 

 p. 286 ; Alder, Mag. Zool. and Bot., II, p. 116; Thompson, 

 Ann. and Mag. Nat. Hist., VI, p. 18; Valvata spirorbis, Dra- 

 pernaud, p. 41, pi. 1, f. 32, 33 ; Tnrton, Man., p. 131, f. 115 ; 

 Brard, p. 187, pi. 6, f. 15, 16; Turbo cristatus, Maton and 

 Racket, Linn. Tr., VIII, p. 169; Helix cristata, Montagu, 

 Test. Brit., p. 460, pi. 1, f. 7, 8. 



Valvata minuta, of Drapernaud, pi. 1, f. 36, 37, 38, repre- 

 sents the young shell; Turton, Man., p. 132, f. 117. 



Shell discoidal, consisting of four cylindrical volutions, flat- 

 tened ahove, and umhilicate beneath; exposing nearly all the 

 inner volutions, these are slightly striated transversely; aperture 

 quite orbicular, attached to but not interrupted by the body 

 volution ; peristome as thick as the other parts of the shell, and 

 slightly oblique. Diameter one-tenth of an inch. 



Found in canals and ditches in Britain, and is a very common 

 - in almost all parts of Ireland. 



Family VIII. — Lymn^ecea. 



Shell spiral, generally with a smooth external surface; margin 

 of the outer lip always acute, and not reflected. Animals am- 

 phibious, usually destitute of an operculum. 



Genus 37 Lymn^a — Lamarck. 



Shell oblong, thin, sometimes elongated and acutely tur- 

 reted ; spire always produced; aperture large, entire, oblong, 

 generally straitened, and somewhat acuminate above and round- 

 ed below ; outer lip acute ; the lower part of the inner lip 

 ascending on the pillar, forming an oblique plait or fold, and 

 rising, spreads more or less over the columella, or front of the 

 body volution ; external surface smooth, frequently polished. 

 Destitute of an operculum. 



1. Lymn.ea stagnalis, pi. XV, f. 19 and 21 First Ed., 



pi. 42, f. 19 and 21. 



Lymnmus stagnalis, Lamarck, An. San. Vert., VI, pt. 2nd, 

 ]>. 159 ; Drapernaud, p. 51, pi. 2, f. 38, 39; Pfoiffer, p. 86, pi. 



I, f. 19; Turton, Man., p. 121, f. 104; Alder, Mag. Zool. and 

 Bot., p. 114; Brard, p. 133, pi. 5, f. 1 ; De Montfort, II, p. 

 268; Sowcrby, Genera, f. 1 ; Rossmassler, I, p. 95, pi. 2, f. 49; 

 Thompson, Ann. and M«g. Nat. Hist., VI, p. 45 ; Stagnicola 

 vulgaris, Leach, Moll., p. 145; Lymneus major, Jeffreys, Linn. 

 Tr., XVI, p. 375 ; Li)iinea stagnalis, Fleming, Brit. An., p. 

 273; Helix stagnalis, Montagu, Test. Brit., p. 367, pi. 16, f. 8; 

 Donovan, Brit. Sh., II, pi. 51, f. 2; Brown, Wernerian Mem., 



II, p. 530. 



Shell very thin, brittle, oblong-oval, subulate, pellucid, and 

 horn-coloured ; body large, longitudinally striated, generally 

 crossed by a few raised spiral ridges; spire acute, consisting of 

 live or six volutions, tapering to a fine point, and separated by a 

 deep suture; aperture oval, a little narrower above than below, 

 and occupying more than half the length of the shell ; outer lip 

 thin, but not reflected; pillar lip reflected on the columella, with 

 an oblique fold, behind which is a slight umbilicus. 



This shell is subject to some variety. F. 22, 23, pi. XV, is 

 a thin and less ventricose variety, to which Montagu gives the 

 specific name of fragile*, p. 369, pi. 16, f. 7- 



Fig. 20 is the representation of a young shell. 

 The very fine specimen from which f. 22 and 23 were drawn, 

 I obtained in a small stream on a flat meadow near Clonoonev 

 Barracks, King's County, Ireland, where they were plentiful of 

 that size. 



2. Lymn^a palustris, pi. XV, f. 17, 18. — First Ed., pi. 

 42, f. 17, 18- 



Lymnteus palustris, Lamarck, An. San. Vert., VI, pt. 2nd, 

 p. 160; Drapernaud, p. 52, pi. 2, f. 40 and 42 ; Pfeiffer, p. 80, 

 pi. 4, f. 20; Turton, Man., p. 123, f. 107; Rossmassler, Icon., 

 I, p. 96, f. 51, 52 ; Brard, p. 136, pi. 5, f. 6, 7 ; Alder, Mag. 

 Zool. and Bot., II, p. 114; Thompson, Ann. and Mag. Nat. 

 Hist., VI, p. 45; Forbes, Mai. Mon., p. 14; Lymnceus com- 

 munis, Jeffreys, Linn. Tr., XVI, p. 276; Stagnicola communis, 

 Leach, Moll., p. 142; Limnea palustris, Fleming, Brit. An., p. 

 274; Helix palustris, Montagu, Test. Brit., p. 373, pi. 16, f. 

 10; Donovan, Brit. Sh., pi. 175; Helix stagnalis, Pennant, 

 Brit. Zool., IV, p. 86, pi. 13, f. 13. 



Shell oblong-ovate, subpellucid, brownish horn-coloured ; 

 body subcylindrical ; spire consisting of four or five well defined, 

 slightly rounded volutions, terminating in a sharp apex, slightly 

 wrinkled langitudinally, and sometimes traversed by distant, 

 slight, irregular transverse ridges, particularly on the body volu- 

 tion, producing a facetted appearance; aperture oval, occupying 

 nearly the half of the shell, inside frequently of a deep choco- 

 late, or purplish-brown; outer lip thin; inner lip a little reflected 

 on the columella, with a small umbilicus behind. Length gene- 

 rally about three-quarters of an inch; breadth three-eights. It 

 sometimes, however, occurs larger. 



This species is subject to great variety, both in proportions 

 and colour. F. 4, 5, 7, 14, 15, 16, and 23, pi. XV, are varie- 

 ties ; f. 26 is a variety of a deep blackish-brown, and is variety 

 b of Drapernaud, p. 52, pi. 2, f . 42 ; f . 1 1 is variety c of the 

 same author, pi. 2, f. 42 ; f. 6, 7 is a variety, with the apex 

 decollated, which is not uncommon, Maton and Racket, Linn. 

 Tr., VIII, pi. 5, f. 8 ; Mag. Nat. Hist., VII, p. 161, f. 32. 

 Found plentifully in ditches, marshes, lakes, and ponds. 

 3. Lymn^a minuta, pi. XV, f. 12, 13.— First Ed., pi. 42, 

 f. 12, 13, and pi. XIV, f. 27- 



Limneus minutus, Drapernaud, p. 53, pi. 3, f. 5, 6; Alder, 

 Mag. Zool. and Bot., II, p. 1 15 ; Brard, p. 138, pi. 5, f. 8, 9 ; 

 Limneus fo'ssarius, Turton, Man., p. 124, f. 108; Limneus 

 ■minutus, Brard, p. 138, pi. 5, f. 8, 9; Limneus truncatulus, 

 Jeffreys, Linn. Tr., XVI, p. 377 ; Thompson, Ann. and Mag. 

 Nat. Hist., VI, p. 32 ; Lymnaa minuta, Lamarck, VI, pt. 2nd, 

 p. 162; Lymncea fossaria, Fleming, Brit. An., p. 274; Helix 

 fossaria, Montagu, Test. Brit., p. 372, pi. 16, f. 9; Brown, Ency. 

 Brit., VI, p. 401; lb., Wernerian Mem., II, p. 530; Turbo 

 rivulus, Walker, Test. Min. Rar., f. 57. 



Shell oblong-ovate, pellucid, of a yellowish horn colour; spire 

 consisting of five or six rounded, and deeply defined volutions, 

 terminating in a sharp apex; aperture ovate, nearly half the 

 length of the shell ; outer lip slightly reflected ; inner lip nar- 

 rowly folded on the columella. Length generally half an inch, 

 but frequently less. . 



This species is not uncommon in many parts of Britain and 

 Ireland. It frequents muddy drains or ditches, and is often to 

 be found in situations, out of water, existing merely by a little 

 moisture. 



