X 
CONTENTS. 
MOLLUSCA. 
General Definition . . . 
PAGE 
. 303 
CHAPTER X. 
MolluscoIba 
Tunicata .... 
Ascidians 
. 312 
CHAPTER XI. 
Acephalous Mollusca . 
. '319 
Ostreadas .... 
CO 
CHAPTER XII. 
Acephalous Mollusca . . 
. 361 
Mvt.ilida? .... 
361 
Cephalous Molluscs . . . 
391 
Their Characteristics . . 
391 
CHAPTER XIII. 
Pulmonary Gasteropods. 
393 
Limneans . . . 
404 
CHAPTKR XIV. 
Non-pulmonary Gasteropobs 
407 : 
Bucciuidaa 
416 
Purpura 
426 
Pterocera 
436 
CHAPTER XV. 
PAGE 
Molluscous Pteropods . . . 441 
CHAPTER XVI. 
Cephalopobous Mollusca . . 445 
Acetabula 445 
Tentaeulifera 470 
CHAPTER XVII. 
Crustaceans 473 
General Definition .... 473 
Crabs and Crayfish . . . 480 
Lobsters 490 
FISHES. 
General Definition .... 493 
CHAPTER XVIII. 
Cartilaginous Fishes . . . 499 
Cyclostomata 499 
Selachia 
Sturiona 545 
CHAPTER XIX. 
Osseous, or Bony Fishes . . 521 
Plectognathi 522 
Lophobranchii 520 
Malacopteiygii gog 
Abdominales 592 
Acanthopterygians . . . 578 
Pharyngians 
