Illustrations of the recent conchology of Great Britain and Ireland, with the description and localities of all the species, marine, land and fresh water

NAYAn1;s.J MOLLUSCA. 81 Sh:11 c~111pressc1I, considerably elongated transl'ersely, thin; anterior s1de ,·erv short · ¡iosterior s1' 1le ,·e,·v ¡ 0 1 ¡ ¡ ¡ • J , · J I g, anc pro1 ucec mto a somcwhat le1wthcned bh111te 1] !in k ¡ · ¡· ¡ . . o , ~a ; unge 11,e arcuatec , a_nd a~cenchng, lts greatest altitude bei11g nearly central; ante- '.·,or sHle rather narrow, and rounded; posterior side descendin" m a waved line; basal line nearly parallel, and undulating ~ nmhones com·ex; outside rather smooth ami co\'ere<l with a hlackish-brown epidermis. ' Said lo be founcl in pomls al Lil'erpool, but I have never met with one from thal locality. An extremely lhin ancl lengthened rnriety, which is coverecl with a redclish-brown epidermis, ancl rather rough on the sur- face. It inhabits Loch Kettrine, Perthshire. Our figure is taken from a specimen procurecl in that locality. Vm·ietg 12. Co:,,iTonTA, pi. XXX, f. i, 8. Shell of moderate thickness; hinge line quite parallel; the ligament hardly protru<ling beyoncl the hinge line; umbones very flat; anterior sidc Yery short, narrow, an<l a little point- ecl; posterior si<le very broad, subroslrale<l, \\·ith a remarkable flcxme, causccl by a strong rib-lik<? proccss, emanaling in both Yah-cs from lhc umboncs, all(I thickcning towar<ls th<? margin; the basal line prominently arcnatcd; shell considcrably inflated, one valve much more convex than thc other. This remarkable variety was found by Thomas Glover, Esq., of Smedley Hill, inhabiting ditcl1es, in a flat meadow, not far from the School 1-Iouse, at Ilepton, ncar Burlon-upon-Trent . Upwards of twenly spccimens wcre obtained by him. Sir Oswalcl Mosley kindly undertook to procure spccimens of this clesirable shell; but on visiting the spot, found the locality com- plctcly destroycd, in consequence of a new bridge having latcly becn built across the Trent; ancl although the ditch in which they were found communirated wilh the river, yet no traces of the shcll could be fouml. GENUS 2.-UNIO,-Bruguicre. Shcll transvcrse, equivalvc, inequilatcral, free, sometimes sub- cor<late, or suborbicular; pearlaccous within; genera U y coverecl with a dark olivaceous epidermis, which is nsually clecorticatecl on the umbones; hinge provided with a shorl, irregular, simple, or a clouble compouncl tooth, which is almost always slriated; with two elongat.ed, comprcssed, lateral teeth, the front one produced, sumelimes obsolete; two muscular impl'essions in cach valve, the superior one compound, or composed of severa) clivisions; ligament externa!. 1. UNIO PICT0RUM, pi. XXXI, f. 7, 8, 9, 10, 1 l. linio pictornm, First Ecl., pi. 26, f. 4 ; Lamal'ck, An. San. Yert., VI, p. 77; Ency. Meth., pi. 2,18, f. ,1; Pfciffer, I, p. 115, pi. 5, f. 9, 1 O; Drapernaud, Moll., pi. 11, f. •1 ; Rossmasslel', I, pl. 3, f. il, a, b; Ib., III, p. 23, pi. 13, f. 19i; lb., IX ami X, P· JO, pi. 45, f. 587 lo 590; Unio 1·ostmtus, Pfeiffcr, I, p. 114, pi. 5, f. 8 ; 11/ga picto1·wn, Sturm, Fauna, VI, p. 2, f. a; Schroeter, Flussconch., pi. 4, f. 6; \Vood, Conch., p. 10<1, pi. 19, f . 3, 4; Donovan, Brit. Sh., III, pi. 89; M9a oualis, Mon- tagn, Test. 13l'it., P· 34; Jlfgse<t pictorum, Turton, Man., p. 20, pi. 2, f. 11 ; Gray's Turton, p. 295, pi. 2, f. 1~, badly figured. Shell thin, transversely oblong-oval, ventncose; umbones a little procluced, all() placed near to the anterior side, which is short, and rounde<l; posterior si<le elongatc<l, and somewhat X pointed; hingc line slightly bcnt; basal line ncarly parallel, all(I a little hollowccl in thc centre; hinge furnishccl with a slrong, doublc, comprcssed, eleratcd, elongaled, crestecl, crenalecl, car- dinal looth in the left valrc, with a perpcndicularly papillosc, striatecl clcft on the side of its posterior portion, on which the looth of the opposite ,·alve rcsls, which locks into a space aborc the shorter cardinal toolh in thc opposite "alve; lateral tceth in both vah·es long, narrow, and sunk at the umboncs,-from whence they take their rise,-becoming more elernted ami acule as they direrge, and exlend thc samc length as the liga- ment; inside highly pearlaceous; rnrying in different specimcns from bluish-white to a rich salmon-colour, with faint, ncarly obsoletc radiations, extencling from the umbones to thc mar- gins; pallial impressions well markcd; anterior muscular im- pressions very deep; posterior oncs distinctly deGned; outside covcred with a smoolh, shining, yellowi~h-green epidermis, but varying in colour from different localitics; with rery indistinct, nearly obsolete, di1·ergent groovcs, radiating from Lhe umboncs to thc mal'gins; ancl with transversc, concent ric, slight furrows, and vcry irregular, lransverse slriro, most conspicuous towards the sidcs. Fig. 11, pi. XXXI, is an externa! view of the teeth of thc hinge. Foun<l in the rivcr Ouse, at York; the Aire, nenr Gargrew; the Severn, near Shrewsbury; in the Aire, nenr Skiplon; lhe Avon, near Lcaminglon, \11 7 arwickshire; ancl severa! olhel' slow l'Unning ri1•ers nnd lakes in Britain. Vai·ictg l, pi. XXXI, f. 7 and 1 O. Rossmassler, III, p. 23, pi. 13, f. 196; lb., I, p. 118, pi. 3, f. 71, a,{¡, The length somewhat more than two-fifths of its breadth; thickness a t.hircl more than íts Jength. This is the ordiuary form of the species. Found in the Ouse, al York; the Severn, ncar Shrewsbury; the canal, near Birmingham; ancl Sir Oswald Mosley, Bart., sent me some beauliful specimens, from the lakc al Rolleslon, with the insides of a rich nacred, pale salmon-colour. In this locality they grow to a very large size, measuring an inch and thrce-quarlers in length, ancl upwards of four inches in breaclth. Vm·ictg 2, pi. XXXI, f. 8. Rossmasslcr, I, p. 117, pl. 3, f. 70, a, U11io tumicli1U1. The posterior side more pointed, that side gradually dimi- nishing both abo1·e and below, from the umbones. Length five-tenths of its brcadth ;· thickness half íts length; cardinal and lateral tecth longer a1HI more prominent lhan in lhe first varicty. Iuhabits the Aire, near Gargrcw; and the river Brothay, which empties itself into Windermere, uear Ambleside. 1/m·iety 3, pi. XXXI, f. 9, Consi<lcrably longer than thc former two varieties, being ncarly a thircl, in proportion lo its breadth; the umboncs more central ami prominent; ami somewhat more inflated. Found in the Don, al Sheffield. 2. Uis10 DESHAYSII, pl. XXXII, f. 1, 2, 3, 4. Unio Dcshagsii, Rossmasslcr, III, p. 23, pi. 13, f. 197; Gib- son, i\ISS. Shell thickish, much elongate<l transversely; hinge line slightly curved; basal line nearly parallel, slightly waved in the centre,