4 
III. Systematic Index = 2231 : — 
Gastropoda 
Amphineura 
Aplacophora 
Polyplacophora 
Prosobranchia 
Opisthobranchia, including Pteropoda and Heteropoda 
Pulmonata ... 
Scaphopoda 
Pelecypoda or Lamellibranchia 
Cephalopoda 
PAGE 
. 27 
. 27 
. 27 
. 27 
. 27 
. 40 
. 41 
. 45 
. 45 
. 53 
