CHAPTER I 



THE MOLLUSCA 



PHYLUM MOLLUSCA, CUVIER 



PALLIATA, Latreille; MALACOZOA, de Blainville; HETERO- 

 GANGLIATA, Owen ; OiocARDiA, Haeckel ; SACCATA, Hyatt). 



GRADE A. ISOPLEURA (Ray Lankester). 

 CLASS I. AMPHINEURA (von Jhering). 

 Order 1. Polyplacophora. 



,, 2. Aplacophora. 



GRADE B. PRORHIPIDOGLOSSOMOUPHA (Grobben). 

 CLASS I. GASTROPODA (Cuvier). 

 SUB-CLASS 1. STREPTONEURA. 

 Order 1. Aspidobranchia. 

 2. Pectinibranchia. 



SUB-CLASS 2. EUTHYNEURA. 

 Order 1. Opisthobranchia. 



2. Pulmonata. 



CLASS II. SCAPHOPODA (Bronn). 

 (No Orders.) 



CLASS III. LAMELLIBRANCHIA (de Blainville). 

 Order 1. Protobranchia. 

 2. Filibranchia. 

 3. Eulamellibranchia, 

 4. Septibranchia. 



GRADE C. SIEHONOPODA (Ray Lankester). 

 CLASS I. CEPHALOPODA (Cuvier). 

 SUB-CLASS 1. TETRABRANCHIA. 



2. DlBRANCHIA. 



Order 1. Decapoda. 

 2. Octopoda. 



1 i 



