C0NTENT8. 



p. 



Introduction 5 



Systematic Section 7 



Opisthobrancliia 7 



Synopsis of Families 7 



Synopsis of Genera and Species 10 



Pteropoda 38 



Synopsis of Families 38 



Synopsis of Genera and Species 38 



Geographical and Bathymetrical Distribution 40 



Description of New Forms 97 



List of Works referred to 103 



Index 108 



Explanation of the Plates 113 



