On the lid, or on a slip of paper or card placed at the head of your columns of trays, write the cla.s.s and order, with its proper number (I., II., etc., as the case may be); then at the top of your left-hand column place the family and its number, and under it the name of the first genus. The species (one in each tray) come next, then the name of the next genus following it, succeeded by its species, and so on.

The object of the young collector should be to obtain examples of as many _genera_ as possible, since a collection in which a great number of genera are represented is far more useful and instructive than one composed of a great many species referable to but few genera. He will also find it very convenient to separate the British Sh.e.l.ls from his general collection, sub-dividing them for convenience into "Land and Fresh-water," and "Marine." Of these he should endeavour to get every species, and even variety, making the thing as complete as possible.

Or a separate collection may be made of all those kinds which he can find within a certain distance of his own home. A collection of this sort possesses, in addition to its scientific worth, an interest of its own, owing to the local a.s.sociations that invariably connect themselves with it.

TABLE OF SOME OF THE MORE IMPORTANT GENERA, SHOWING THE APPROXIMATE NUMBER OF SPECIES BELONGING TO EACH GENUS AND THEIR DISTRIBUTION.

CLa.s.s I.--CEPHALOPODA.

ORDER I.--Dibranchiata.

Section A.--_Octopoda._

Family. Genus. No. of Species. Distribution.

1. Argonauta 4 Tropical seas.

2. Octopus 46 Rocky coasts in temperate and tropical regions.

Section B.--_Decapoda_.

3. Loligo 19 Cosmopolitan.

4. Sepia 30 On all coasts.

5. Spirula 3 All the warmer seas.

ORDER II.--_Tetrabranchiata_.

6. Nautilus 3 or 4 Chinese Seas, Indian Ocean, Persian Gulf.

CLa.s.s II.--GASTEROPODA.

ORDER I.--Prosobranchiata.

Division _a_.--_Siphonostomata._

No. of Family. Genus. Species. Distribution.

1. Strombus 60 W. Indies, Mediterranean, Red Sea, Indian Ocean, Pacific--low water to 10 fathoms.

Pteroceras 12 India, China.

2. Murex 180 On all coasts.

Columbella 200 Sub-tropical regions, in shallow water on stones.

Mitra 350 Tropical regions, from low water to 80 fathoms.

Fusus 100 On all coasts.

3. Buccinum 20 Northern seas, from low water to 140 fathoms.

Eburna 9 Red Sea, India, Australia, China, Cape of Good Hope.

Na.s.sa 210 World-wide--low water to 50 fathoms.

Purpura 140 World-wide--low water to 25 fathoms.

Harpa 9 Tropical--deep water, sand, muddy bottoms.

Oliva 117 Sub-tropical--low water to 25 fathoms.

4. Ca.s.sis 34 Tropical regions, in shallow water.

Dolium 15 Mediterranean, India, China, W.

Indies, Brazil, New Guinea, Pacific.

Triton 100 Temperate and sub-tropical regions, from low water to 50 fathoms.

Ranella 50 Tropical regions, on rocks and coral-reefs.

Pyrula 40 Sub-tropical regions, in 17 to 35 fathoms.

5. Conus 300 Equatorial seas--shallow water to 50 fathoms.

Pleurotoma 500 Almost world-wide--low water to 100 fathoms.

6. Voluta 100 On tropical coasts, from the sh.o.r.e to 100 fathoms.

Cymba 10 West Coast of Africa, Lisbon, Straits of Gibraltar.

Marginella 90 Mostly tropical.

7. Cypraea 150 Warmer seas of the globe, on rocks and coral-reefs.

Ovulum 36 Britain, Mediterranean, W. Indies, China, W. America.

Division _b_.--_Holostomata._

8. Natica 90 Arctic to tropical regions, on sandy and gravelly bottoms, from low water to 90 feet.

Sigaretus 26 E. and W. Indies, China, Peru.

9. Cancellaria 70 W. Indies, China, S. America, E.

Archipelago--low water to 40 fathoms.

10. Pyramidella 11 W. Indies, Mauritius, Australia, in sandy bays and on shallow mud-banks.

Odostomia 35 Britain, Mediterranean, and Madeira--low water to 50 fathoms.

Chemnitzia 70 World-wide--low water to 100 fathoms.

Eulima 26 Cuba, Norway, Britain, India, Mediterranean, Australia--5 to 90 fathoms.

11. Solarium 25 Sub-tropical and tropical--widely distributed.

12. Scalaria 100 World-wide--low water to 100 fathoms.

13. Cerithium 100 World-wide.

Potamides 41 Africa and India, in mud of large rivers.

Aporrhais 3 Labrador, Norway, Britain, Mediterranean--20 to 100 fathoms.

14. Turritella 50 World-wide--low water to 100 fathoms.

Vermetus 31 Portugal, Mediterranean, Africa, India.

15. Melania 160 S. Europe, India, Philippines and Pacific Islands--in rivers.

Melanopsis 20 Spain, Australia, Asia Minor, New Zealand--in rivers.

16. Paludina 60 Northern Hemispheres, Africa, India, China, etc.--in lakes and rivers.

Ampullaria 50 S. America, W. Indies, Africa, India--in lakes and rivers.

17. Litorina 40 On all sh.o.r.es.

Rissoa 70 World-wide--in shallow water on sea-weed to 100 fathoms.

18. Calyptrea 50 World-wide--adherent to rocks, etc.

Crepidula 40 West Indies, Mediterranean, Cape of Good Hope, Australia.

Pileopsis 7 Britain, Norway, Mediterranean, E.

and W. Indies, Australia.

Hipponyx 70 W. Indies, Galapagos, Philippines, Australia.

Phorus 9 W. Indies, India, Javan and Chinese Seas--in deep water.