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CLASSIFICATION. 





Tectlbranchia, 



Infer obranchia, 

 JNudibranchia , 



CoVered-gillg, ) Bulla or 

 i. e., by the mantle, j Bubble. 

 Under-gills, i. e., } 

 under the edge v 

 of the mantle. ) 

 Naked-gills, i. e., ) Glaucus, 

 without Shells. } Doris. 



1, i. e., feet ) Carinaria, 

 the others, f Firola. 



II. ACEPHALA. HEADLESS MOLLUSKS. Four orders. [like gills.) 



(1). CONCHIFERA (Shell bearing) or LAMELLIBKANCHIA, (Plate or leaf- 



(Oyster Family) Ostracece- 



sub-families-^nomuWa?, Anomia. ^ ,, 



P///-,*i///p Pi,, I Monomy- 



PlacunidcB, Placuna. I 

 Ostreida, Ostrea. } aria or 

 Peetinida , Pecten. j g ne 

 Amculida, Avicula. J muscle ' 



(Fresh Water Mussels) 4 Naiades or Unionidce, Unio, Anodon, -i 



Alasmodon. 

 (Salt-water do. ) 4 Mytilaceee, Mytilus, Modiola, Pinna, 



Crenella. 

 4 CAamacc<E-sub-families, 



Tridacnidce, Tridacna. 



^ ' ChamidfB, Chama. 



4 Cardiace(z,.{ do. Carditidee, Cardita. 



Mantle closed behind. 



Siphons united ) Lucinida, Lucina. 



or distinct. I Veneridce, Venus. Dimyaria 



(_ Crassitcllidce, Crassitella, (or having 



Sub-order INCLUSA (inclosed, i. e., within the two 



mantle, which has but one opening for the muscles.) 



passage of the foot.) 



Families Mactridce, Mactra. 



Myidce, Mya. 



Solemyida, Solemya. 



Saxicavidte, Saxicava. 



Pandoridce, Pandora. 



Solenida, Solen (Razor Shell). 



Pholadidce, Pholas. 



Teredinidce, Teredo (Wood or Ship Worm. 

 Enclosed in a tube j Tubicolidte, Aspergillum ) or Watering- 

 but not attached. ( Gastrochaena. ) pot. 



C Arm-footed, i. e., having two long spiral ^ Terebratula, 

 (2). BRACHIOPODA, ^ arms each side of the mouth capable > Lingula, 

 ( of protrusion. } Orbicula. 



( Coated, i. e., body enveloped in an elastic ) including 



{ tunic or coa-t, ) 



the Ascidians (or Mollusks of a Leathern bottle-shape). 

 Gr. Moss-animals, i. e., largely aggregated like ) 

 corallagineous Zoophytes. ) 



(3). TUNICATA, 



' 



Brvozoa. 

 "v * 03 * 



