VI CONTENTS. 



CHAPTER IV. PAGE 



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- 

 laneous 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. Reproduc- 

 tion : of lost parts ; by gemmation ; viviparous ; alternate ; 

 oviparous. Development 21 



CHAPTER V. 



CLASSIFICATION. Affinities; analogies; species; genera; fami- 

 lies ; the quinary system 55 



CHAPTER VI. 



NOMENCLATURE. Synonyms; authorities; types 59 



ABBREVIATIONS 61 



SYNOPSIS OF THE GENERA. 

 CLASS I. CEPHALOPODA. ORDER I. DIBRANCHIATA 62 



SECTION A. OCTOPODA 64 



Fam. I. Argonautid<B. Argonauta 66 



Fam. II. Octopodida. Octopus, Piunoctopus, Eledone, 



Cirroteuthis, Philonexis 67 



SECTION B. DECAPODA 68 



Fam. III. Teuthidce. Loligo, Gonatus, Sepioteuthis, Belo- 

 teuthis, Geoteuthis, Leptoteuthis, Cranchia, Sepiola, Lo- 

 ligopsis, Cheiroteuthis, Onychoteuthis, Enoploteuthis, 

 Ommastrephes 



