MOLLUSCA. 



133 



its slope being convex, and about a third shorter than the pos- 

 terior side ; colour cream-white. Breadth nearly two-twelfths 

 of an inch ; length not quite a twelfth. 



Found among the roots of aquatic plants, in a ditch between 

 Aberdeen and Spital. 



Genus Psammobia — (Page 101.) 



8. Psammobia Florida, pi. XXXIX, f. 30. 

 Psammobia florida, Turton, Biv., p. 86, pi. , f. 6. 



Shell transversely oblong-ovate, rather convex, equally round- 

 ed at both sides ; hinge with a single cleft tooth in one valve, 

 with a pit on each side for the reception of two teeth in the 

 opposite valve; surface smooth, with close-set, concentric stria?, 

 and minute longitudinal ones; variously marked with transverse 

 zones of red or yellow, and longitudinally radiated; inside vary- 

 ing from pale yellow to rich reddish-lilac. Length half an inch ; 

 breadth one inch. 



Inhabits the Western coast of England, and the Eastern of 

 Ireland. 



9. Psammobia costulata, pi. XXXIX, f. 34. 

 Psammobia costulata, Turton, Biv., p. 87, pi. 6, f. 8. 



Shell transversely oblong-oval, thin, slightly angular at the 

 anterior end, where there are about twelve fine, divergent, lon- 

 gitudinal ribs emanating from the umbones, which are straight, 

 a little prominent, and nearly central ; whole surface with very 

 minute, longitudinal, and somewhat more open transverse stria?; 

 colour varying from pale yellow to deep purple, and marked 

 with blotches and stripes of pale crimson ; hinge with a slightly 

 cleft tooth in one valve, locking between two in the other, one 



of which is slightly cloven ; inside same colour as the external 

 surface, but more vivid. Length half an inch ; breadth an 

 inch. 



Found at Torbay and the Irish Channel. 



Genus Sphenia (Page 104.) 



4. Sphenia costulata. 



Sphenia costulata, Macgillivray, Moll. Ab., p. 301. 



Shell convex, very thin, subdiaphanous and glossy, trans- 

 versely-ovate, equally rounded at both sides, the anterior one 

 considerably shorter ; umbones small, and slightly protruding ; 

 whole surface with faint, concentric striae, and with about 

 fifteen slightly elevated, radiating ribs ; tooth thin, and of an 

 elongated lamellar form ; colour white. Length a twelfth of 

 an inch ; breadth a twelfth and a half. 



Found among shell sand, from the Bay of Cruden, by Mr. 

 Murray. 



Genus 1 Stylifer. — Broderip. 



Shell thin, pellucid, turbinated; spire narrow, its apex a little 

 off the perpendicular; aperture wide below, and narrowed above, 

 with an acute termination. 



The shells of this genus burrow in the rays of star fish. 



1. Stylifer astericola, p. 10, pi. X, f. 40, 41. 



Phasianella sti/lifera. 



The genus Stylifer is now transferred to the family Serpu- 

 lacea, but we have great doubts as to this being its proper 

 situation in the system. 



ALPHABETICAL LIST 



THE PRINCIPAL AUTHORS TO WHICH REFERENCE HAS BEEN MADE IN THE FOREGOING WORK. 



Adams, Micros. Essay on the Microscope, Sec., by George Adams, 2nd 



Edit. 4to. London, 1798. 

 Adams, Linn. Tr. Description of some minute British Shells, by John 



Adams. Transactions of the Linnean Society, V. 

 Alder, Mag. Zool. and Bot. Notes on the Land and Fresh Water Mol- 



lusca of Great Britain, Sec. Magazine of Zoology and Botanv. II, 



by Joshua Alder. 

 Catalogue of Land and Fresh Water Testaceous Mollusca, found 



in the Vicinity of Newcastle-upon-Tyne, &c. Transactions of the 



Natural History Society of Northumberland. 1830 lb., Sup. 



1817. 

 Alten, J. W. Von. Systematiche abhandlung iiber die Erd-und Fluss- 



conchylier Augsbourg, &c. 1812. 

 Bean, Mag. Nat. Hist. Undescribed Shells in Loudon's Magazine of 



Natural History, VIII, by William Bean. 1834. 

 Bennet, Zoological Journal, I, p. 298. Description of an hitherto 



unpublished Species of Buccinum, by E. T. Bennet. 1824. 

 Berkeley, Zool. Journ. Description of several British Shells, &c. Zoo- 

 logical Journal, IV. and V, by the Rev. M. G. Berkeley. 1828-9. 

 Brard, Coq. de Paris. Histoire des Coquilles terrestres et fluviatiles qui 



vivent aux Environ de Paris, by C. Prosper Brard, 2 vols. Svo. 



1808. 

 Broderip, Zool. Journ. Description of two new Species of Buccinum, 



by W. J. Broderip. Zoological Journal, V. 1835. 

 2 L 



Brown, Conch. Text Book. The Conchologist's Text Book, according 

 to the system of Lamarck, by Captain Thomas Brown. 1833. 



Edin. Journ. Nat. and Geo. Science. Description of several 



new British Shells. Edinburgh Journal of Natural History and 

 Geographical Science, I. 1827. 



Article Conchology. Encyclopedia Britannica, sixth Edition, 



VI, p. 385. 



Article Conchology. Encyclopedia Edinensis, II. p. 533. 



Article Conchology. Popular Encyclopedia, II. p. 374. 



, Account of the Irish Testacea. Memoirs of the Wernerian 



Natural History Society, II. 1817. 

 Bruguiere, Encyclopedie Methodique. Article Vers. 4to. 1792. 

 Chemnitz. New System of Conchology, in German, by F. H. W. 



Martini and J. H. Chemnitz, 11 vols. 4to. 1769-1788. 

 Clarke, Ann. and Mag. Nat. Hist. On the Species of the Genus Limax 



occurring in Ireland, by the Rev. B. J. Clarke. Annals and Maga- 

 zine of Natural History, XV, p. 332. 

 Da Costa. Historia Naturalis Testaceorum Britannia, English and 



French, by Emanuel Meades Da Costa, 4to. London, 1778. 

 Dillwyn, L. W. Descriptive Catalogue of Recent Shells, 2 vols. 

 Donovan, Edward. Natural History of British Shells, 5 vols, royal 



Svo. 1804. 

 Drapernaud, J. P. R. Histoire Naturelle des Mollusques Terrestres et 



Fluviatiles de la France, 4to. 1805. 



