CONTENTS. 



PART I. 



CHAPTER I. 



Ov THE PoSITIOlSr OF THE MoLLUSCA IN THE AnIMAL KiNGI>OM, 



— Characters of the five primary groups, or sub-kirgdoms : — 

 Yertebrata — Mollusca — Annulosa — Ccelenterata — Protozoa. 

 Their antiquity 1 — 3 



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



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



Habits and Economy of the Mollusca. — 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. — Longe^dty of molluscous 

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



Structure and Physiology of the Mollusca. — Nervous 

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

 system ; lingual teeth ; secretions. — Circulating system ; 

 aquiferous canals. — Respiratory system. — The shell, its 

 - composition and structure ; nacreous, fibrous, and porcel- 

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

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

 collated shells ; monstrosities ; colours ; the operculum ; 

 homologies. — Temperature and hybernation. — Reproduction : 

 of lost parts ; by gemmation ; ^dviparous ; alternate ; o^apa- 

 rous. — Development 15 — 45 



Classification. — Affi nities ; analogies; species; genera; families; 

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

 viations 45 — 49 



