Part 2

19. M. TRUNCATA, _Linn._--_M. ovalis_ and _Sphænia Swainsoni_ (young).--Various localities and depths, C. Truncated at end.

20. M. ARENARIA, _Linn._--Herne Bay, Portsmouth, etc., C. Tapering at end.

PANOPÆA. Burrows in mud.

21. P. NORVEGICA, _Spengl._--_P. glycimeris_, _P. arctica_.--Scarborough, Zetland (90 fath.), Rr. Quadrate.

21*. P. ALDROVANDI, _Lamk._--Cornwall, one specimen, _Jeffreys_. Oblique.

CORBULA. Dredged in mud and sand.

22. C. NUCLEUS, _Lamk._--_C. striata_, _Mya_, and _C. inæquivalvis_.--Dublin, Torquay, Forth, 4 to 80 fath., C. Valves unequal, beaked.

23. C. ROSEA, _Brown_.--Weymouth, Rr. as Brit. Valves not beaked.

24. C. OVATA, _Forbes_.--Isle of Man, Rr. Oval, truncated at end.

SPHÆNIA. Burrows in foliaceous shells.

25. S. BINGHAMI, _Turt._--_Corbula B._--Torquay, Guernsey, Swansea, Forth, etc., R.

NEÆRA. Lives incrusted in sand.

26. N. COSTELLATA, _Desh._--_Corbula c._, _N. sulcata_.--Loch Fyne, Rr. Radiately 3-ribbed.

27. N. CUSPIDATA, _Olivi_.--Forth, Northumberland, Cape Clear, etc., Mr. Pear-shaped.

28. N. ABBREVIATA, _Forbes_.--Loch Fyne, Mc. Radiately 1-ribbed.

PLATE II.

POROMYA. On mud, in deep water.

Fig.

1. P. GRANULATA, _Nyst._--_P. anatinoides_, Forbes.--Skye, R.

1*. P. SUBTRIGONA, _Jeffreys_.--Shetland, Mr. Minute, posteriorly expanded. See Pl. IX.

PANDORA.

2. P. ROSTRATA, _Lamk._--_Tellina inæquivalvis_, Linn.; _P. margaritacea_ and _inæquivalvis_.--S. Devon?, Guernsey, R. as Brit. Valves long.

3. P. OBTUSA, _Leach_.--_Solen Pinna_, Mont.--S. Devon, Dorset, Mc. Ire., R. Valves short and broad.

LYONSIA. With byssal attachment.

4. L. NORVEGICA, _Chemn._--_Mya_ and _Anatina n._, _Mya_ and _Anatina striata_, _M. nitida_, _Lyonsia elongata_, _Myatella_, and _Osteodesma_.--Tenby, Bantry, Oban, etc., 5 to 80 fath. With movable ossicle on hinge.

THRACIA. Laminarian and Coralline.

5. T. DISTORTA, _Mont._--(_Mya_) _Anatina_ and _Amphidesma d._, _Th. truncata_.--Distribution general, but not common. Short, truncated, irregular.

6. T. CONVEXA, _Wood_.--(_Mya_) _Anatina_ and _Amphidesma c._, _T. declivis_.--S. Devon, Bantry Bay, Arran, etc., Mc. Inflated.

7. T. PHASEOLINA, _Lamk._--_Amphidesma p._, _T. declivis_.--Various localities and depths, C. Oval, obliquely truncated.

8. T. PUBESCENS, _Pult._--(_Mya_) _Anatina_ and _Amphidesma p._, _T. declivis_.--S. Devon, Cornwall, Belfast, etc., C. Oblong, straightly truncated.

9. T. VILLIOSULCA, _Macgillivray_.--_T. ovata_, Brown.--Exmouth, Swansea, Bantry Bay, etc. Various depths, Mc.

COCHLODESMA. Laminarian and Coralline.

10. C. PRÆTENUE, _Pult._--(_Mya_) _Anatina_, _Ligula_, and _Amphidesma pr._--Dorset, Devon, Man, Bantry B., Oban, etc., (25 to 60 fath.), R. Spoon-shaped process on hinge.

CERATISOLEN. Burrows in sand.

11. C. LEGUMEN, _Linn._--(_Solen_) _Psammoiia_ and _Solenicurtus l._--Exmouth, Swansea, Bantry, etc., C. Hinge nearly central.

SOLEN. Burrows perpendicularly in sand.

12. S. PELLUCIDUS, _Penn._--Various British localities, 6 to 100 fath. Curved; hinge not terminal.

13. S. ENSIS, _Linn._--Eng., Scot., Ire., generally 5 to 15 fath., C. Arched and slender.

14. S. MARGINATUS, _Pult._--_S. vagina_, Penn., not Linn.--Exmouth, Clyde, Cork, etc., littoral to 10 fath., Mc. Straight, with terminal constriction.

15. S. SILIQUA, _Linn._--_S. novacula_, _S. ligula_.--Eng., Scot., Ire., many places; littoral and laminarian, C. Straight, end not constricted.

DIODONTA.

16. D. FRAGILIS, _Linn._--(_Tellina_) _Psammobia f._, _Tellina jugosa_ and _ochroleuca_.--Dublin, Tenby, Weymouth, R. Oval or wedge-shaped.

16*. D. BARLEEI, _Jeffr._--Arran, Rr. Minute, subquadrate.

SOLECURTUS.

17. S. COARCTATUS, _Gmel._--_S. cultellus_, _S. emarginatus_, _S. antiquatus_, etc.--Torbay, Anglesea, Man, Skye, etc., R. Oblong, smooth.

18. S. CANDIDUS, _Renieri._--(_Solen_) _S. strigilatus_, Turt., not Linn., _Psammobia scopula_.--S. Devon, Dublin, etc., R. Striated.

SYNDOSMYA.

19. S. PRISMATICA, _Mont._--(_Ligula_) _Mya_ and _Amphidesma p._--Weymouth, Forth, Dublin, Antrim, etc., littoral, Mc. More pointed and narrow than _S. intermedia_.

20. S. TENUIS, _Mont._--(_Mactra_) _Amphidesma t._--Dorset, Scarborough, Antrim, etc., 5 to 100 fath., Mc. Short, subtrigonal.

21. S. INTERMEDIA, _Thompson._--_Mya_ and _Syndosmya nitida_, _Abra profundissima_.--In mud, 6 to 100 fath., Zetland, Skye, Cape Clear, etc., R. Broader and more pointed than _S. prismatica_.

22. S. ALBA, _Wood._--(_Mactra_) _M._ and _Amphidesma Boysii_ and _A. album_.--Brit. co. generally, C. Short, rounded, oval.

PLATE III.

PSAMMOBIA. Inhabits sand and mud.

Fig.

1. P. FERROENSIS, _Chemn._--(_Tellina_) _T. incarnata_, _T. radiata_, _T. trifasciata_, _T. truncata_.--Brit. co. generally; coralline, C. Oblong, keeled and angulated behind.

2. P. COSTULATA, _Turt._--_P. discors._--Torbay, Cornwall, Skye, etc., R. Ribbed behind.

3. P. TELLINELLA, LAMK.--_P. florida._--Exmouth, Guernsey, Tenby, Bantry B., Oban, Zetland, etc., 5 to 50 fath., C. Oval, smooth.

4. P. VESPERTINA, _Chemn._--(_Lux V._) _Solen_, _Sanguinolaria V._, _Tellina depressa_, _variabilis_.--Weymouth, Scarborough, Tenby, Bantry, etc., Guernsey, C. Not angular nor keeled behind.

TELLINA.

5. T. CRASSA, _Penn._--_T. maculata_, _T. rigida_.--S. Devon, Guernsey, Man, Tenby, Bantry, Forth, etc., low-water to 15 fath., C. Thick, orbicular.

6. T. BALAUSTINA, _Linn._--Birterbuy, Skye, Exmouth, Rr. as British.

7. T. DONACINA, _Linn._--_T. trifasciata_, _T. variegata_, _T. Llantivyi_.--Various British loc., and S. Europe, 5 to 50 fath., C. Wedge-shaped.

8, 9. T. PROXIMA, _Brown._--Var. _T. calcarea_ (9), _T. ovalis_, _T. sordida_, _Sanguinolaria sordida_, _Macroma tenera_.--Skye, etc., R.

10, 11. T. PYGMÆA, _Phil._--Devon, Cork, Shetland, etc., 8 to 50 fath., C. Smaller, more convex, and more truncate than _T. donacina_.

12, 13. T. TENUIS, _Da Costa._--_T. planata_, _T. polita_, _T. exigua_.--On sandy shores, in various localities, C. Flat, thin.

14. T. INCARNATA, _Linn._--_T. squalida_, _T. depressa_.--Devon, Bantry, Tenby, R. Flat, beaked.

15. T. SOLIDULA, _Pult._--_T. rubra_, Da Costa, _T. carnaria_, _T. zonata_, _Psammobia solidula_, _T. Balthica_.--All British coasts; littoral, C. Thick, inflated.

16. T. FABULA, _Gronovius._--_T. discors._--On sandy shores generally, C. Valve with oblique striæ (omitted by error).

ERVILLIA.

17. E. CASTANEA, _Mont._--(_Donax_) _Mesodesma c._, _Capsa c._--Cornwall and Scilly Isles, R. Ligament within.

SCROBICULARIA.

18. S. PIPERITA, _Gmel._--Generic syn.: _Mya_, _Venus_, _Trigonella_, _Mactra_, _Lutraria_, _Listera_.--Specific syn.: _hispanica_, _borealis_, _plana_, _gaditana_, _Listeri_, _compressa_.--Scarborough, Southend, Swansea, Cork, Clyde, C. Broad, compressed.

DONAX.

19. D. ANATINUS, _Lamk._--_D. trunculus_, Linn.?, _Cuneus vittatus_, _D. ruber_ (young).--Brit. co. generally, sandy shores, C. Broad; margin crenulated.

20. D. POLITUS, _Poci._--(_Tellina_) _D._ and _Capsa complanata_.--S. Devon, Bantry Bay, etc., Mr. Smooth; inner edge not crenated.

MACTRA. Lives on sandy beaches.

21. M. STULTORUM, _Linn._--(_Cardium_) _Tellina radiata_, _Trigonella r._, _M. cinerea_, _M. magna_.--British co. generally, C.

22. M. ELLIPTICA, _Brown._--British co. generally, C. Oval.

23. M. SUBTRUNCATA, _Costa._--_M. lactea_, _M. triangula_, _M. crassatella_.--Brit. co. generally, C. Obliquely cuneiform.

24. M. HELVACEA, _Chemn._--_M. glauca_, _M. neapolitana_.--Odd valves found dead in Cornwall, R. Large, obliquely oval.

25. M. SOLIDA, _Linn._--_Trigonella zonaria_ and _gallina_.--Brit. co. generally, C. Trigonal, thick.

26. M. TRUNCATA, _Mont._--Forth, Cork, Cornwall, etc., C. Trigonal, deep, thick.

PLATE IV.

LUTRARIA. Inhabits mud.

Fig.

1. L. INTERMEDIA?, _Sowb._--Perhaps only the young of _L. elliptica_.

2. L. ELLIPTICA, _Lamk._--_Mactra lutraria_, Linn.--Scarborough, Torbay, Dublin, Forth, Lerwick, etc., C. Broad, oval.

3. L. OBLONGA, _Chemn._--(_Mya_) _L. solenoides_, _L. hians_, _Mactra hians_, _Chama magna_.--Cornwall, Devon, etc., Mc. Arched, narrow.

TAPES. Burrows in mud and stone.

4, 5. T. PULLASTRA, _Wood._--_Venus pullastra_, _V. perforans_ (var. f. 4), _Venerupis nucleus_, _Pullastra vulgaris_, etc.--Plymouth, Scarborough, Swansea, Forth, etc., C.

6. T. DECUSSATA, _Linn._--(_Venus_) _V. litterata_, _V. florida_, _Venerupis_ and _Pullastra d._--S. Devon, Weymouth, Tenby, etc., Mc. Oblong, coarsely decussated.

7. T. AUREA, _Gmel._--(_Venus_) _V. nebulosa_, _V. ænea_, _V. nitens_, _V. sinuata_, _Pullastra a._--Cornwall, Sussex, Bantry Bay, Loch Ryan, Mc. Yellow within.

8. T. VIRGINEA, _Linn._--(_Venus_) _V. rhomboides_, _V. sarniensis_, _V. virago_, _Cuneus fasciatus_.--Various British loc., C. Pink within.

LUCINOPSIS, _Forbes_ and _Hanley_. Sandy ground.

9. L. UNDATA, _Pennant._--(_Venus_) _V. sinuosa_, _V. incorrupta_, _Lucina undata_.--Exm., Scarborough, Man, etc., 5 to 80 fathoms, M.R. Orbicular, flexuous at side.

ARTEMIS.

10. A. EXOLETA, _Linn._--(_Venus_) _Cytherea e._, _Pectunculus capillaceus_.--Sandy ground, on Brit. co. generally, low-water to 80 fath., C. Compressed; striæ coarse.

11. A. LINCTA, _Pult._--(_Venus_) _V. sinuata_, _Cytherea sinuata_.--Various Brit, loc., C. Dorsal edge sloping; striæ fine.

VENUS.

12. V. CASINA, _Linn._--_V. reflexa_, _V. lactea_, _V. discina_.--Northumberland, S. Devon, Man, Bantry, Skye, etc., Mc. Concentrically laminated.

13. V. VERRUCOSA, _Linn._--_V. erycina_, _V. cancellata_, etc.--Devon, Cornwall, Channel Isls., etc., C. Ventricose, warted.

14. V. FASCIATA, _Donov._--Various southern Brit, loc., C. Round, with thick ribs.

15. V. OVATA, _Pennant._--Brit. co. generally, C. Oval, radiately ribbed.

16. V. STRIATA, _Donov._--_V. gallina_, _V. Pennantii_, _V. rugosa_.--Brit. co. generally. Shores and deep water, C.

ASTARTE.

17. A. TRIANGULARIS, _Mont._--_Mactra_ and _Goodallia_, _minutissima_ and _triangularis_.--Northern parts of Britain, 15 to 20 fathoms, C. Minute, triangular.

18. A. ELLIPTICA, _Brown._--_Crassina e._, _Crassina ovata_, and _C. sulcata_. Scotland, 5 to 10 fath., mud, M. C. Oblong, smooth near the margin.

19. A. SULCATA, _Costa._--(_Pectunculus_) _V. scotica_ and _Damnoniensis_, _Crassina sulcata_, etc.--Devon, Cornwall, Bantry, etc., C. Thickly ribbed.

20. A. COMPRESSA, _Mont._--(_Venus_) _Venus and Crassina Montagui_, _Cyprina comp._--Scarborough, Northumbria, Bantry Bay, Firth of Forth, 7 to 40 fath., M. C.

21. A. CREBRICOSTATA, _Forbes._--Zetland and Skye (dead), R. Ribs more numerous than in _A. sulcata_.

22. A. ARCTICA, _Gray._--(_Crassina_) _Venus borealis_, _Astarte compressa_.--Aberdeen, Zetland, St. Andrew's bay, etc., Rr. Lenticular, not ribbed.

CYTHEREA.

23. C. CHIONE, _Linn._--(_Venus._)--Plymouth, S. Devon, Falmouth, Carnarvon, 12 to 20 fath., Mr.

PLATE V.

CYPRINA.

Fig.

1. C. ISLANDICA, _Linn._ (_Venus._)--_C. vulgaris_, _V. mercenaria_.--Brit. co. generally, most abundant north, 5 to 80 fath. Oval, with thick epidermis.

CIRCE.

2. C. MINIMA, _Mont._ (_Venus._)--Gen. _Cyprina_ and _Cytherea triangularis_, _apicialis_, _Cyrillii_, _minuta_.--Guernsey, Cornwall, Milford Haven, Clyde, Bantry Bay, etc., 10 to 50 fath., C.

ISOCARDIA.

3. I. COR, _Linn._ (_Chama._)--_I. hibernica_, _Cardita cor._--Dublin, Skye, etc., Mc. Heart-shaped, beaks coiled.

CARDIUM, or _Cockle_.

4. C. PYGMÆUM, _Donovan._--_C. exiguum._--Herne, Sark, Weymouth, Zetland, Bantry Bay, 5 to 50 fath., Mc. Hinder side large, angular.

5. C. PAPILLOSUM, _Poli._--Guernsey, St. Martin's Port, _Jeffreys_, R. Rather rounded, equally ribbed and grained.

6. C. PUNCTATUM, _Broc._, C. NODOSUM, _Turt._--_C. scabrum_, Ph.--Exmouth, Falmouth, Galloway, etc., Mc. Angular behind.

7. C. FASCIATUM, _Mont._--_C. elongatum_, _C. ovale_, _C. parvum_, _C. rubrum_ (young).--Various Brit. loc., Mr.

8. C. SUECICUM, _Loven._--_C. Swediense_, Reeve, _C. Loveni_, Thompson.--Down, Oban, Zetland, 30 to 70 fath., Rr. Oval, equally ribbed.

9. C. ACULEATUM, _Linn._--_C. ciliare_ and _parvum_ (young).--S. Devon, Mc. Thin, oblique, with thorn-like tubercles; interstices of ribs smooth.

10. C. RUSTICUM, _Linn._--_C. tuberculatum_, Linn.?--Paignton, Torbay, Velvet Strand, Dublin co., Mc. Thick, not oblique, coarsely wrinkled.

11. C. ECHINATUM, _Linn._--_C. mucronatum_, _C. spinosum_.--Brit. co. generally, mud and sand, 7 to 80 fath. Oblique, wrinkled; hinder tubercles sharp.

12. C. EDULE, _Linn._--_C. vulgare_, _C. zonatum_, _C. obliquum_, _C. crenulatum_, _C. rusticum_.--Brit. co. generally. Common eatable, Cockle.

13. C. NORVEGICUM, _Spengler._--_C. lævigatum_, _C. serratum_, _C. oblongum_, _C. Pennantii_.--Brit. co. generally. Sand and gravel, 15 to 80 fath. Smooth, variegated when young.

LUCINA.

14. L. DIVARICATA, _Linn._ (_Tellina._)--_Cardium arcuatum_, _L. arcuata_, _commutata_.--Near Falmouth, 20 fath., Rr. Rounded, with diverging ribs.

15. L. FLEXUOSA, _Mont._ (_Tellina._)--_Venus sinuosa_, _Amphidesma flexuosa_, _L. sinuata_; gen. _Cryptodon_, _Axinus_, and _Ptychina_.--Clyde, Bantry, Anglesea, etc., 7 to 80 fath., Mc. Thin, with a fold behind.

16. L. BOREALIS, _Linn._ (_Venus._)--_Tellina radula_, _Lucina r._, _L. alba_.--Many Brit. loc., 1 to 90 fath., C. Lenticular, concentrically laminated.

17. L. LEUCOMA, _Turt._--_L. lactea_, not Linn., _Loripes lactea_.--Torbay, Scarborough, Bantry Bay, etc., low-water to 80 fath., C. Round, smooth.

18. L. SPINIFERA, _Mont._ (_Venus._)--_Myrtea s._, _L. hiatelloides_.--Dartmouth, Plymouth, Hebrides, etc., 8 to 100 fath., M. R. Oval; dorsal margin spinose.

DIPLODONTA, _Mont._

19. T. ROTUNDATA, _Mont._ (_Tellina._)--_T. undata_, _Lucina r._, _D. dilatata_.--Dorset, Devon, Tenby, Bantry Bay, etc., 7 to 25 fath., R.

CLAUSINA, _Jeffreys._

20. C. FERRUGINOSA, _Forbes_, (_Kellia._)--Skye, Loch Fyne, etc., 30 to 100 fath., C. Concentrically ribbed, minute, oval.

21. C. CROULINENSIS, _Jeffreys._--Croulin Island, Shellands, R. Suborbicular.

22. C. ABYSSLICOLA, _Jeffreys._--Not ribbed, R.

PLATE VI.

MONTACUTA.

Fig.

1. M. FERRUGINOSA, _Mont._ (_Mya._)--_M. oblonga_, _M. glabra_, _Tellimya elliptica_, _Erycina f._--S. Devon, Scarborough, Tenby, Cape Clear, etc., Mr. Wedge-shaped, long.

2. M. BIDENTATA, _Mont._ (_Mya._)--_Erycina_, _Petricola_, and _Tellimya b._--Newcastle, Weymouth, Dublin, etc. Burrows in dead shells, Mr. Short, subquadrate.

3. M. SUBSTRIATA, _Mont._ (_Mya._)--_Erycina_ and _Tellimya s._--Devon, Tenby, Durham, Zetland, Bantry Bay, etc., on spines of _Spatangus_, deep water, C. Minute, with diverging striæ.

TURTONIA.

4. T. MINUTA, _O. Fabr._ (_Venus._)--_Mya purpurea_, etc.--Scarborough, Tenby, Cork, Oban, etc., C.

KELLIA.

5. K. SUBORBICULARIS, _Mont._ (_Mya._)--_Bornia inflata_, _Tellina_ and _Tellimya s._--Anglesea, Portland, Zetland, etc., low-water to 60 fath., Mr.

6. K. LACTEA, _Brown_, (_Tellimya._)--Brit. co. generally. More oblong than _K. sub._

7, 8. K. RUBRA, _Mont._ (_Cardium._)--_Poronia r._, etc.--Numerous localities; littoral, C.

LEPTON.

9. L. SQUAMOSUM, _Mont._--_Solen_ and _Lutraria s._--Salcombe Bay, Tenby, Cork, etc., R. Flat, subquadrate.

10. L. NITIDUM, _Turt._ (_Kellia._)--Torbay, Skye, R. Less square and flat than _L. squamosum_.

11. L. CONVEXUM, _Alder._--Bantry Bay, Rr. Convex, granulated.

12. L. CLARKIÆ, _Clark._--Exmouth, Plymouth, Zetland, Rr. Minute, oval, smooth.

13. L. SULCATULUM, _Jeffr._--Annals, Feb. 1859. Guernsey, Mc. Concentrically wrinkled.

GALEOMMA. Adheres to rocks by byssus.

14, 15. G. TURTONI, _Sowb._--Channel Islands, and Exmouth. Oblong, gaping.

CYCLAS. Inhabits fresh-water.

16. C. CORNEA, _Linn._ (_Tellina._)--_Sphærium c._, Scopoli, _C. rivalis_, etc.--Ponds and ditches everywhere. Equilateral, subquadrate.

17. C. PISIDIOIDES, _Gray._--_C. cornea_, var., Brit. Moll.--Ditches and ponds, C. Oblique, and light coloured.

18. C. RIVICOLA, _Leach._--_Cardium nux_, etc.--Thames, etc. Large, oval, wrinkled.

19. C. CALICULATA, _Drap._-_C. lacustris_, etc.--Newcastle, Bristol, etc., Mr. With a ridge at the apex.

20. C. LACUSTRIS, _Drap._--_pallida_, Gray.--Regent's Park, etc., Mr. Oval, light.

PISIDIUM. Inhabits fresh-water.

21. P. OBTUSALE, _Pfeiffer._--_P. pusillum_, var.?

22. P. PUSILLUM, _Turton_, (_Tellina._)--_Cyclas fontinalis_ and _gibba_.--In marshes and ponds at various places, C. Includes _P. obtustale_?

23. P. AMNICUM, _Müller_, (_Tellina._)--_T. rivalis_, _Cyclas palustris_, _C. obliqua_.--British rivers, etc., generally. _C. obliqua_ ribbed.

24. P. NITIDUM, _Jennyns._--Battersea, Swansea, etc., C. Thick, dark, blunt.

25. P. HENSLOWIANUM, _Sheppard_, (_Tellina._)--_Cyclas appendiculata_, _P. acutum_.--Cambridge, Swansea, etc., R. With a projection on the umbones.

26. P. PULCHELLUM, _Jennyns._--_Cyclas fontinalis_, etc.--Various localities, C. Ridged.

27. P. CINEREUM, _Alder._--_Cyclas c._--Various localities, Mc. Smooth.

28. P. ROSEUM, _Scholtz._--Various loc., with _P. pulchellum_ and _P. nitidum_ M. C. Subquadrate; animal pink.

PLATE VII.

UNIO. Fresh-water Mussel with hinge-teeth.

Fig.

1. U. MARGARITIFERUS, _Linn._ (_Mya._)--_Alasmodon m._, _A. arcuata_, _U. elongata_, _U. sinuata_.--R. Conway; rivers in Cumberland, Wales, Ireland, etc., Mc. Long, thick, arched.

2. U. PICTORUM, _Linn._ (_Mya._)--_U. ovalis_, _U. rostrata_, _U. limosus_, _U. Deshayesii_, etc.--Various British rivers, C. Long, oval, not wedge-shaped behind.

3. U. TUMIDUS, _Retz._--_Mya_ and _Unio ovalis_, _M. depressa_, _M. ovata_, _Myscei o._, _M. solida_.--Thames, and various British rivers, C. More solid, deep, and wedge-shaped than _U. pictorum_.

ANODONTA. Fresh-water Mussel, without teeth.

4. A. CYGNEA, _Linn._ (_Mytilus._)--_M. anatinus_, _M. stagnalis_, _M. paludosa_, _Symphonota cy._--Britain and Europe generally, in rivers and canals, C.

DREISSINA, _Beneden._

5. D. POLYMORPHA, _Pallas_, (_Mytilus._)--London Docks, Edinburgh Canal, C.

MODIOLA, _Lamarck._

6. M. MODIOLUS, _Linn._ (_Mytilus._)--_M. umbilicatus_, _M. curtus_, _M. vulgaris_.--British coasts generally, C. Large, brown, not rayed.

7. M. OVALIS?, _Sowb._--_M. tulipa_ (_radiata_), var., Brit. Moll., now named provisionally. Less tumid, and with longer and more gradually sloped dorsal line than _M. radiata_, Rr.

8. M. RADIATA, _Hanley_, _Brit. Marine Conch._--_M. tulipa_, Brit. Moll., Mc. Tumid, radiated.

9. M. BARBATA, _Linn._ (_Mytilus._)--_M. Gibbsii._--Jersey, Torbay, Milford Haven, Youghal, R. as Brit. Barbs of epidermis serrated.

10. M. PHASEOLINA, _Philippi._--Guernsey, Falmouth, Scotland, Mc. Small barbs of epidermis not serrated.

11. M. CUPREA, _Jeffreys_, _Ann. Nat. Hist. Jan. 1859_.--In the stomach of a bird shot at Scarborough, Rr. Minute, rhomboidal, smooth.

CRENELLA, _Brown._

12. C. NIGRA, _Gray_, (_Modiola._)--_Mytilus_ and _Modiola discrepans_, _depressa_, _compressa_, _discors_.--Scotland, R. Broad and compressed behind.

13. C. DISCORS, _Linn._ (_Mytilus._)--_Modiola d._ and _discrepans_.--Brit. co. generally, among seaweeds, C. Wedge-shaped and lobed.

14. C. MARMORATA, _Forbes._--_Mytilus_ and _Mediola discors_, _discrepans_, and _tumida_.--Brit. co. generally, Cc. Rhomboidal, marbled.

15. C. COSTULATA, _Risso._--Exmouth, Cornwall, Swansea, Herm. Wedge-shaped, marbled, strongly-ribbed.

16. C. RHOMBEA, _Berkley_, (_Modiola._)--_M. Prideauxiana._--Guernsey, Torbay, Penzance, etc.; coralline, R.

17. C. DECUSSATA, _Montagu_, (_Mytilus._)--_C._ and _Modiola elliptica_, _cicercula_, and _faba_.--Scarborough, and a few northern localities, 5 to 50 fath., Mc.; Norway, etc. Subquadrate, decussated, minute.

MYTILUS, _Linn._

18. M. EDULIS, _Linn._--_M. vulgaris._--Brit. co. generally, Cc. Byssal margin swelled.

19. M. UNGULATUS, _Linn. Syst. Nat._--_M. edulis_, var. _M. incurvatus_ (Hoof-Mussel).--Cornwall, Guernsey, etc., Mr. Byssal margin bent inwards, lower margin broad and straight.

20, 21. M. GALLOPROVINCIALIS, _Lamk._--_M. edulis_, var. _M. dilatatus_?, _M. pellucidus_? (young, f. 21), _M. subsaxatilis_?--British Channel, etc., C. Dorsal margin dilated, beak advancing.

PLATE VIII.

NUCULA, _Linn._

Fig.

1. N. NUCLEUS, _Linn._ (_Arca._)--_N. margaritacea_, _Glycimeris argentea_.--Brit. co. generally, 7 to 90 fath., C. Thick, obtuse; beaks terminal.

2. N. DECUSSATA, _Sowerby._--_N. sulcata_, _N. Polii_.--Hebrides, Loch Fyne, Dublin Bay, 30 to 50 fath., Mr. Large, striated; beak not terminal.

3. N. RADIATA, _Hanley._--_N._ and _Arca nucleus_ and _radiata_.--Torbay, Milford Haven, Arran, etc., 10 to 70 fath., Mc. Prolonged anteriorly, rayed.

4. N. NITIDA, _Sowerby._--_N. nucleus_, var.--Numerous British loc., 1 to 35 fath., C. Shining, ends rather pointed.

5. N. TENUIS, _Montagu_, (_Arca._)--North British co., 40 to 100 fath., sand, C. Thin, inner edge not crenated; beak terminal.

LEDA, _Schum._ Beaked behind.

6. L. CAUDATA, _Donovan_, (_Arca._)--_Arca_ and _Nucula minuta_ and _rostrata_.--North co., C.; south co., R. 10 fath. to deep water. Ridged.

7. L. PYGMÆA, _Munster_, (_Nucula._)--_N._ and _L. tenuis_, _gibbosa_, and _lenticula_.--Skye, Hebrides, Croulin Isl., 25 to 50 fath. Minute, smooth. Size (omitted) one-fifth of an inch.

ARCA, _Linnæus._

8, 9. A. LACTEA, _Linn._--_A. barbata_, _A. Modiolus_, _A. crinita_, _A. perforans_, _A. Gaimardii_, var. f. 8; _A. Quoyi_, var. f. 9.--Penzance, Ilfracombe, Bantry Bay, Guernsey, etc. Adhering to shells and stones, 15 to 20 fath., C. Beaks approaching, radiately striated.

10. A. TETRAGONA, _Poli._--_A. Noæ_ and _imbricata_.--Many Brit, loc., C. (12 to 50 fath.). Broad area between beaks.

11. A. RARIDENTATA, _S. Wood._--_A. pectunculoides._--Skye, Hebrides, etc., Scot. Cape Clear, 40 to 60 fath., Mr. Minute, teeth few.

12. A. NODULOSA, _Ph._--E. Zetland, Shetland Isls., Rr.

PECTUNCULUS.

13. P. GLYCIMERIS, _Linn._ (_Arca._)--_A._ and _P._ and _Glycimeris pilosa_, _orbicularis_, _undata_, and _marmorata_.--Brit. co. generally, 15 to 60 fath., C.

LIMOPSIS.

14. L. PELLUCIDA, _Jeffreys_, _Ann. Nat. Hist. Jan. 59_.--Dredged in sand at Guernsey, Rr.

AVICULA.

15. A. TARENTINA, _Lamk._--_Mytilus_ and _Avicula hirundo_, etc.--Bantry Bay, Devon, etc., R.

PINNA.

16. P. PECTINATA, _Linn._--_P. fragilis_, _muricata_, _ingens_, _lævis_, _papyracea_, _rotundata_, _elegans_.--Dorset, Milford Haven, Hebrides, Cape Clear; deep water, Mc.

OSTREA.

17. O. EDULIS, _Linn._--_O. vulgare_, etc.--Various natural and artificial beds, in England, Scotland, and Ireland. The common Oyster.

ANOMIA.

18. A. EPHIPPIUM, _Linn._--_A. electrica_, _A. squamula_, _cepa_, etc.--Brit. co. generally, 1 to 30 fath., C. Pearly and irregular; beak marginal, curved.

19. A. ACULEATA, _Müller._--_A. striolata._--Brit. co. generally, Mc. Small, with spinous sculpture.

20. A. STRIATA, _Lovén._--Hebrides, R. Rayed, striated, with apex not marginal.

21. A. PATELLIFORMIS, _Linn._--_A. undulata._--Cape Clear, etc., 1 to 50 fath., Mr. Flat, ribbed.

LIMA.

22. L. SUBAURICULATA, _Montagu_, (_Pecten._)--_L. nivea_, _sulcata_, etc.--Plymouth, Man, Zetland, Belfast, etc., Mr. Nearly straight.

23. L. HIANS, _Gmel._ (_Vitræa._)--_L. tenera_, _fragilis_, _aperta_, etc.--Channel Isls., Penzance, Oban, Belfast, etc., Mc. Oblique, gaping at sides.

24. L. LOSCOMBII, _Sowerby._--_Pecten_ and _Ostrea_ and _Lima fragilis_ and _bullata_.--Many Brit. loc., 10 to 50 fath., Mc. Oblique, closed at sides.

PLATE IX.

PECTEN. Free, except 1.

Fig.

1. P. PUSIO, _Pennant_, (_Ostrea._)--_P._, _O._, and _Hinnites distortus_ and _sinuosus_.--Brit. co. generally, 15 to 90 fath., C. Irregular, attached to stones, etc.