CONTENTS. 



PAET I. 



CHAPTER I. 



PAGE 



On the Position of the Moleusga in the Animal Kingdom. 

 — Cliaracters of the five primary groups, or sub -kingdoms :— 

 Yertebrata—MoUusca—Anjiulosa—Coelenterata— Protozoa. 



Their antiquity 1~^ 



Glasses of Mollusga. — 1. Cephalopoda. — 2. Gasteropoda. — 



3, Pteropoda. — 4. Brachiopoda. — 5. Lamellibranchiata ... 3 — 7 



Habits and Economy of the Mollusga. — Sedentary tribes, their 

 mode of attachment ; locomotive tribes, their means of pro- 

 gression ; situations frequented by shell-fish. — Food : vege- 

 table, infusorial, and animal feeders. — Use of shell-fish to 

 other animals for food; use of shells for ornamental and 

 other purposes ; prices of shells. — Longevity of molluscous 

 animals ; tenacity of life ; fecundity ; oviposition 7 — 15 



Strugtuee and Physiology of the Mollusga. — Nervous 

 system ; organs of sense. — Muscular system. — Digestive 

 system ; lingual teeth ; secretions. — Circulating system ; 

 aqiiiferous canals. — Eespiratory system. — The shell, its 

 composition and structure; nacreous, fibrous, and porcel- 

 lanous shells ; epidermis ; erosion of fresh- water shells. — 

 Eormation and growth of the shell ; adult characters ; de- 

 collated shells ; monstrosities ; colours ; the operculum ; 

 homologies. — Temperature and hybernation. — Reproduction : 

 of lost parts ; by gemmation ; vi-vdparous ; alternate ; ovipa- 

 rous. — Development 15 — 45 



Classification. — Affinities; analogies; species; genera; families; 

 the quinary system ; synonyms ; authorities ; types ; abbre- 

 Yiations , 45 — 49 



