582 



INDEX. 



Fifth Class of MoUusca — continued. 



Tectibranchiata .... 



For the most part naked slugs 



Sea-hares ..... 



Inferobranchiata 



Cyclobranchiata 



Limpets . . . . . 



Coat of mail-shell, chiton 



Nudiljranchiata 



Naked-gilled moUusca, common ou the British coast 



Theh- great diversity and beauty of form 



Homed doris .... 



Tritonia hombergi 



Young of nudibranchiate gasteropods 



Heteropoda .... 



Their fin-shaped foot used as an oar 



CHAPTER XIX. 



Sixth Class of MoUusca : — 



Pteropoda ..... 



Their locomotive apparatus 

 Northern olio, its instruments of prehension 

 Limacina helicina, its exquisite shell 

 Hyalpea ...... 



Cleodora, its luminosity 



CHAPTER XX. 



Seventh Class of IMollusca : — 



Cephalopoda . .... 



Their remarkable habits and appearance 



Their ink 



Mechanism of their suckers 



Enormous size of some cephalopoda 



The common poulpe, its terrible aspect 



Its powerful arms . . . 



Its chameleon-like change of colour 



Its amusing stratagems 



Calamaries, their additional arms 



Then- plate of horn ... 



Squids, used for bait . 



Theu' eyes .... 



Hooked-squids, the tenacity of their grasp 



Cuttle-fishes .... 



Common cuttles, their ink . 



Cuttle-fish bone 



Eggs of the sepia 



The argonaut, fiction of the ancients respecting it 



Nautilus, its chambered shell 



Characteristic structiu-e of nautilus 



Its food ..... 



