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

~l'!ACTIUCEA.] MOLLUSCA. 107 nre separatcd by a triangular hiat.us , bclow the umbo; inside glossy, whitc. Lcngth a littlc more than a quartcr of an inch; hrcadth nearly half an inch. Founcl at l3elton Sands, ncar Dunbar; and Turton says il inhabits thc \V estcrn coasts. ;;. TI::LLDIYA GLAllllA, pi. XLII, f. 20, 21. Tellim!J" glabm, First Ecl., pi. 14, f. 20, 21. Shcll clliptical, moclcralcly inllatcd, lhin, smooth, extremely glossy; umboncs obtusc, placed consiclcrably lo one side; shorter side obliqncly snbt runcated, the othcr roundccl; hinge with one broad primary 100th in cach valvc, and a large hiatus immedi- ately uncler the umboncs in both Yalves; inside smooth, glossy ; margins sharp. Length nearly a quarter of an inch; breadth about half an inch. Found by General Binghnm, at Dunbar; in his cabinct, and also thal of Lady J ardine. 6. TELLl~IYA DIDENTATA, pi. XLIV, f. 8, 9. A11ati1w biclcntata, Firsl Ed., pi. 11, f. 8, 9; 1llontac11ta biclentala, Turton, Biv., p. 60; M!Ja biclcntata, Montagu, p. 44, pi. 2, f. 5; Brown, Ency. Brit., VI, p. 405. Shell suboval, thin, comprcssecl, smooth, white, but not glossy; umboncs small, siluate nearcst to one side, and slightly bent; hinge with two broacl, ercct, laminatccl teeth in one valve, these stand obliqnely outwards from lhe beak, and some- what clistant from each othcr, between these, ancl immediately under the umbo, is a slight triangular cavity for sustaining the cartilage; opposite valve with a triangular hiatus, situate imme- diately below the umbo, for the reception of the opposite teeth. Length an eighth of an inch ; breaclth rather more. Founcl in Salcomb Bay, burrowing in dccayed thick oyster shells. 7. TELLIMYA SUllSTJllATA, pi. XL, f. 23. T ellimy" subst?-iata, First Ecl., pi. 16, f. 23; 11/ontacuta sub- st1·iata, Turton, Biv., p. 59, pi.11, f. 9, 10; Ligttla s11bsti-iata, Montagu, Sup., p. 25. Shell subovale, somewhat oblique, a little inflated, slightly contracted in thc midclle of the valves, subpellucid, white, sometimcs with a ferruginous tinge; umbones prominent, straight, and not quite central; onc side short ancl narrowed, the opposite ample and rouncled; surface covercd with elcYated, distant, nearly obsolcte striro; hingc with a clefl sidc tooth, a narrow grooved tooth on the opposile sidc, and a hiatus hetween them, immediatcly under thc umbo; tecth in thc opposite valve Yery indistinct, if any, with a central triangular hiatus. Diameter about the tenth of an inch. Found attached to corallincs, on the Devonshire coast; and to spincs of the Echinus ¡nwp1tre11s, to which thcy are attached by slencler filamentary processes, emanating from the middle of the margin. Scctio1i III.-Ligamcnt inter11al; shcll gaping at tlie sides. GENUS 34-MAcTRA,-LitÍnrous. Shell generally thin, sometimes thick; equivalve, for the most part nearly equilateral, and more or less regularly triangular; slightly gaping at onc end, ami almost imperccptibly so at the other ; each vah·e with one V shaped cardinal tooth, the point being ncxt thc umbo, diverging from it, and in sorne spccics t.he limbs are disunite<l at the base, so as to give the appearance of two distinct teeth; close on the posterior side is situate a Yery thin, sharp tooth; immcdiately behind the angular tooth is placed the pit for the reception of thc Jigament, ami project- ing somewhat within the shell; one \'alYe with two lntcral teeth on cach side, and or.e 011• both sides in the other, clivcrging from the bcaks, near the marbnin of the shcll and fittin" into the > b space between the two in the opposite valve; two lateral, remole, muscular impressions; pallial impression with a small sinus; ligament consisting of two portions, the one considerably larger than the other and interna!, and the other half external ; two strong, lateral, muscular impressions in cach ,·all'e; pallial impression interrupted by a small sinus. Scction I .-Lateml tceth smooth; shellf,·11gile. l. 11:facTnA GLAUCA, pi. XLI, f. J. 11facl1'a glauca, First Ed., pi. 15, f. 1 ; Montagu, p. 571 ; Donovan, IV, pi. 125; Turton, Bi1•., p. 73; Flcming, p. 42S ; JJlactra hclvacea, Lamarck, V, p. 473. Shell subtriangular, thin ; anterior side slightly wrinklecl; umbones somewhat obtuse; a little reflected, with a narrow intervcning gap; surface of a cream-yellow colour, vcry 6nely striated transversely, and ,yith irregular, broad ami narrow gln11- eous radiations of a pale brown-colour; inside of a pale cream- colour, or purple; margins thin, ami sharp. Found on the coast of Cornwall; but I am not aware that any living specimens have been met with, the Jocalit y not having becn yet detected. 2. MACTRA S1·uLTonuM, pi. XLI, f. 2. Macti-a Stulto1·um, First Ecl., pi. 15, f. 2; Montagu, p. !.M ; Donovan, III, pi. 106; Turton, Biv., p. 72 ; Maton ancl Hackctt, p. 69. Shcll subtriangular, thin, semipellucid; mnbones centrnl, rathcr prominent, and frequcntly of a purplish lme; sicles nearly cqual; surface covered with a yellowish-brown, or fawn-colourecl epidermis, frequcntly of a cream-colour, beneath whir.h the shell is elegantly radiated with deeper brown, or brownish-purple, irregular in number, sorne broad, others narrow, and frequently with transverse zones of a palcr colour ; inside pale lilac, which frequently penetrates to the outsidc, giving it the samc cast of eolour; when the epidermis is removed, it is found to be covered with faint, somewhat irregular, transverso striro. Vary- ing in length from an inch and a half to nearly two inches; ami in breadth from one inch and three-quarters to nearly two inchcs and a half. This species is found on mosl of the Dritish and Irish coasts. Sorne specimens are entirely dest itute of rays. 3. MACTRA DEALBETA, pi. XLI , f. 8, 9. 11factra dealbcta, First Ed., pi. 15, f. 8, 9; Pultency, Cat. Dorset, p. 31 ; Montagu, p, 95, pi. 5, f. 1 ; Maton and Rackett, p. 68, pi. 1, f. 10; Fleming, p. 429. Shell transversely ovate, thin, fragile, moderately inflated ; umbones not quite central, but situate ncarer the larger side; · gaping a little al the narrowcr side; colour grayish or brownish- white, very 6nely striated concentrically, and with a few coarser transverse wrinkles; midclle tooth in onc valve broad, cleft, ancl angulatcd close to the bcak; lateral teeth not ,•ery remole; inside glossy, white; margin plain, with a sharp edge. Found at Weymouth, by Mr. Bryer, but is extrcmely rare; if it is not merely a variety of !ti. Stultormn.