GEOGRAPHICAL DISTRIBUTION OF LAND MOLLUSCA (_continued_)--THE ETHIOPIAN, NEARCTIC, AND NEOTROPICAL REGIONS 328 CHAPTER XII DISTRIBUTION OF MARINE MOLLUSCA--DEEP-SEA MOLLUSCA AND THEIR CHARACTERISTICS 360 CHAPTER XIII CLASS CEPHALOPODA 378 CHAPTER XIV CLASS GASTEROPODA--AMPHINEURA AND PROSOBRANCHIATA 400 CHAPTER XV CLASS GASTEROPODA (_continued_): OPISTHOBRANCHIATA AND PULMONATA 427 CHAPTER XVI CLASSES SCAPHOPODA AND PELECYPODA 444 BRACHIOPODA (RECENT) CHAPTER XVII INTRODUCTION--SHELL--BODY--DIGESTIVE SYSTEM--BODY CAVITY--CIRCULATORY SYSTEM--EXCRETORY ORGANS--MUSCLES--NERVOUS SYSTEM--REPRODUCTIVE SYSTEM--EMBRYOLOGY--HABITS--DISTRIBUTION--CLASSIFICATION 463 BRACHIOPODA (FOSSIL) CHAPTER XVIII INTRODUCTION--DIVISION I. ECARDINES--EXTERNAL CHARACTERS--INTERNAL CHARACTERS--DIVISION II. TESTICARDINES--EXTERNAL CHARACTERS--INTERNAL CHARACTERS--SYNOPSIS OF FAMILIES--STRATIGRAPHICAL DISTRIBUTION--PHYLOGENY AND ONTOGENY 491 SCHEME OF THE CLASSIFICATION ADOPTED IN THIS BOOK MOLLUSCA Class Order Sub-order Section { OCTOPODA (p. 382). { { Phragmophora (p. 386). { =Dibranchiata= { { Sepiophora (p. 388). { { { { { DECAPODA { Chondrophora { _Myopsidae_ (p. 389). { { { { _Oigopsidae_ (p. 390). =CEPHALOPODA= { { { NAUTILOIDEA { Retrosiphonata (p. 393). { { { Prosiphonata (p. 395). { =Tetrabranchiata= { { { AMMONOIDEA { Prosiphonata (p. 397). { { { Prosiphonata (p. 397).