CHAPTER I 



THE MOLLUSCA 



PHYLUM MOLLUSCA, CUVIER 



( = PALLIATA, Latreille ; MALACOZOA, de Blainville ; HETERO- 

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



GRADE A. ISOPLEURA (Ray Lankester). 

 CLASS I. AMPHINEURA (von Jhering). 

 Order 1. Polyplacophora. 

 2. Aplacopbora. 



GRADE B. PRORHIPIDOGLOSSOMORPHA (Grobben). 

 CLASS I. GASTROPODA (Cuvier). 

 SUB-CLASS 1. STREPTONEURA. 

 Order 1. Aspidobranchia. 

 2. Pectinibrancbia. 



SUB-CLASS 2. EUTHYNEURA. 

 Order 1. Opisthobranchia. 

 2. Pulmonata. 



CLASS II. SCAPHOPODA (Bronn). 

 (Xo Orders.) 



CLASS III. LAMELLIBRANCHIA (de Blainville). 

 Order 1. Protobrancbia. 

 2. Filibranchia. 

 3. Eulamellibrancbia. 

 4. Septibrancbia. 



GRADE C. SIPHONOPODA (Ray Lankester). 

 CLASS I. CEPHALOPODA (Cuvier). 

 SUB-CLASS 1. TETRACRANCHIA. 

 2. DIBRANCHIA. 

 Order 1. Decapoda. 

 2. Octopoda. 



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