Contents 



PART I 

 DEVELOPMENT 



Page 

 I— INTRODUCTION 



Problems to Be Solved 1 



Difficulties op Research 2 



Literature 3 



Sexes Distinct in American Oyster 3 



Occasion op the Present Work 4 



II— THE OYSTER AND ITS MODE OF LIFE 



Species 8 



Distribution 9 



Habitat 9 



Food 9 



Breeding 10 



III— REPRODUCTIVE CELLS 



Embryology 11 



The Sexes 12 



Eggs and Sperms 12 



Fertilization (Fecundation) 14 



IV— DEVELOPMENT PREVIOUS TO THE SWIMMING STAGE 



Oosperm and Segmentation Stages 18 



Embryonic Stages 19 



V— LARVAL OR SWIMMING STAGES 



A Well-marked Change of State ' 23 



The Shell-less Larva 23 



The Shell-bearing Larva 28 



Plankton 31 



Bivalve Larv^ of Plankton Collections 33 



Identification of Oyster and Other Bivalve Larv^ 34 



Time of Occurrence of Oyster Larv.^ in Plankton 37 



Literature on the Larva 38 



VI— ORGANS OF THE LARVA 



Shell 42 



Velum 44 



Foot 45 



Mantle 48 



Gills 49 



Adductor Muscles 49 



The Intestinal Canal 49 



Pigment Spots 49 



Otocysts 50 



Nerve Ganglia 50 



The Heart 50 



Sections of Larv^ 50 



