TABLE OF CONTENTS. 



PAGE 



SYNOPSIS OF THE CLASSIFICATION 4 



ACEPHALA 20 



SPECIFIC DESCRIPTIONS OF THE ACEPHALA 35 



GASTEROPODA 225 



SPECIFIC DESCRIPTIONS OF THE GASTEROPODA 226 



LlST OF THE EXOTIC SPECIES THAT HAVE BEEN IMPROPERLY 



ADMITTED INTO THE BRITISH LIST 509 



APPENDIX 511 



INDEX . . 529 



