Placuna 4 Scinde, North Australia, China--in brackish water.

3. Pecten 176 World-wide--from 3 to 40 fathoms.

Lima 20 Norway, Britain, India, Australia-- from 1 to 150 fathoms.

Spondylus 70 Tropical seas--attached to coral-reefs.

4. Avicula 25 Britain, Mediterranean, India-- 25 fathoms.

Perna 18 In tropical seas--attached.

Pinna 30 United States, Britain, Mediterranean, Australia, Pacific--low water to 60 fathoms.

5. Mytilus 70 World-wide--between high and low water mark.

Modiola 70 British and tropical seas--low water to 100 fathoms.

6. Arca 400 In warm seas--from low water to 200 fathoms.

Pectunculus 58 West Indies, Britain, New Zealand-- from 8 to 60 fathoms.

Nucula 70 Norway, j.a.pan--from 5 to 100 fathoms.

7. Trigonia 3 Off the coast of Australia.

8. Unio 420 World-wide--in fresh waters.

Anodon 100 North America, Europe, Siberia--in fresh waters.

Division _b_.--_Siphonida._

9. Chama 50 In tropical seas on coral reefs.

10. Tridacna 7 Indian and Pacific Oceans, Chinese Seas.

11. Cardium 200 World-wide--from the sh.o.r.e line to 140 fathoms.

12. Lucina 70 Tropical and temperate seas--sandy and muddy bottoms--from low water to 200 fathoms.

Kellia 20 Norway, New Zealand, California--low water to 200 fathoms.

13. Cyclas 60 Temperate regions--in all fresh waters.

Cyrena 130 From the Nile and other rivers to China--and in mangrove swamps.

14. Astarte 20 Mostly Arctic--from 30 to 112 fathoms.

Cra.s.satella 34 Australia, Philippines, Africa, etc.

15. Cyprina 1 From Britain to the most northerly point yet reached--from 5 to 80 fathoms.

Circe 40 Britain, Australia, India, Red Sea-- 8 to 50 fathoms.

Isocardia 5 Mediterranean, China, j.a.pan--burrowing in sand.

Cardita 54 Tropical seas--from shallow water to 150 fathoms.

16. Venus 176 } World-wide--buried in sand, from low Cytherea 113 } water to 100 fathoms.

Artemis 100 Northern to tropical seas--from low water to 100 fathoms.

Tapes 80 Widely distributed--burrowing in sand, from low water to 100 fathoms.

Venerupis 20 Britain, Canaries, India, Peru--in crevices of rocks.

17. Mactra 125 World-wide--burrowing in sand.

Lutraria 18 Widely distributed--burrowing in sand.

18. Tellina 300 In all seas--from the sh.o.r.e line to 15 fathoms.

Psammobia 50 Britain, Pacific and Indian Oceans-- from the littoral zone to 100 fathoms.

Sanguinolaria 20 W. Indies, Australia, Peru.

Semele 60 Brazil, India, China, etc.

Donax 68 Norway, Baltic, Britain--in sand near low water mark.

19. Solen 33 World-wide--burrowing in sand.

Solecurtus 25 Britain, Africa, Madeira, Mediterranean--burrowing in sand.

20. Mya 10 North Seas, W. Africa, Philippines, etc.--river mouths from low water to 25 fathoms.

Corbula 60 United States, Britain, Norway, Mediterranean, W. Africa, China-- from 15 to 80 fathoms.

21. Anatina 50 India, W. Africa, Philippines, New Zealand.

Thracia 17 Greenland to Canaries and China--from 4 to 120 fathoms.

Pandora 18 Spitzbergen, Panama, India--from 4 to 110 fathoms, burrowing in sand and mud.

22. Gastrochaena 10 W. Indies, Britain, Red Sea, Pacific Islands--from sh.o.r.e line to 30 fathoms.

Saxicava Arctic Seas, Britain, Mediterranean, Canaries and the Cape--in crevices and boring into limestone and rocks.

Aspergillum 21 Red Sea, Java, New Zealand--in sand.

23. Pholas 32 Almost universal--from low water to 25 fathoms.

Xylophaga 2 Norway, Britain, S. America--boring into floating wood.

Teredo 14 In tropical seas--from low water to 100 fathoms.

SOME WORKS OF REFERENCE.

MOLLUSCA IN GENERAL.

"A Manual of Mollusca." By Dr. S. P. Woodward.

"Tabular View of the Orders and Families of the Mollusca." Published by the Society for Promoting Christian Knowledge.

"Ca.s.sell's Natural History," latest edition, article on the Mollusca. By Dr. Henry Woodward.

BRITISH MOLLUSCA.

"A History of British Mollusca and their Sh.e.l.ls." By Professor E. Forbes and S. Hanley.

"British Conchology." By J. G. Jeffreys.

"Common Sh.e.l.ls of the Sea-sh.o.r.e." By Rev. J. G. Wood.

BRITISH LAND AND FRESH-WATER MOLLUSCA.

"Land and Fresh-water Mollusca indigenous to the British Isles." By Lovell Reeve.

"A Plain and Easy Account of the Land and Fresh-water Mollusca of Great Britain." By Ralph Tate.

[Ill.u.s.tration]

FOSSILS.

BY

B. B. WOODWARD.