56 HANDBOOK OF SHELLS. 



On the lid, or on a slip of paper or card placed at the head of 

 your columns of trays, write the class 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 instruc- 

 tive than one composed of a great many species referable to but 

 few genera. He will also find it very convenient to separate 

 the British Shells 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 separ- 

 ate 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 

 tis own, owing to the local associations 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 DISTRI- 

 BUTION. 



CLASS I. CEPHALOPODA. 



ORDER I. Dibranchiata. 



Section A. Octopoda. 



No. of 

 Family. Genus. 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. 



