CHAPTER I 
THE MOLLUSCA 
PHYLUM MOLLUSCA, Cuvier 
(=Pavuata, Latreille; Mavacozoa, de Blainville; HETERO- 
GANGLIATA, Owen; Orocarp!IA, Haeckel ; SaccaTa, Hyatt). 
GrapvE A. IsopLEuRA (Ray Lankester). 
Cxass I. AMPHINEURA (von Jhering). 
Order 1. Polyplacophora. 
, 2. Aplacophora. 
GRADE B. PRORHIPIDOGLOSSOMORPHA (Grobben). 
Cuass I. Gasrropopa (Cuvier). 
Sus-CLass 1. STREPTONEURA. 
Order 1. Aspidobranchia. 
» 2. Pectinibranchia. 
Sup-CLass 2. EUTHYNEURA. 
Order 1. Opisthobranchia. 
» 2. Pulmonata. 
Cuass H. ScapHoropa (Bronn). 
(No Orders.) 
Crass Ii. LAMELLIBRANCHIA (de Blainville). - 
Order 1. Protobranchia. 
» 2. Filibranchia. 
, 3 HEulamellibranchia. 
, 4. Septibranchia. 
GRADE ©. SrPHONOPODA (Ray Lankester). 
Cuass I. CEPHALOPODA (Cuvier). 
Sus-Cuass 1. TETRABRANCHIA. 
i 2. DIBRANCHIA. 
Order 1. Decapoda. 
» 2. Octopoda. 
i I 
