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Corbis. Shell transverse, equivalve, without any irregular fold on the 

 anterior margin, having the beaks opposite and curved inwards; two cardinal 

 teeth, two lateral teeth, the posterior of which is nearest the hinge. The 

 muscular impressions simple. 



C. fimbriata, 2 fossil species. 



Lucina. Shell suborbicular, inequilateral; beaks small, pointed, and 

 oblique; two diverging, cardinal teeth, one of which is fixed, and which vary 

 or disappear with age; two lateral teeth, sometimes obsolete, the posterior 

 approaches nearest to the cardinal teeth; two muscular impressions, very 

 separate, the posterior extending in the shape of a band, sometimes very long. 

 Ligament external. 



L. Jamaicensis, 

 ' Pennsylvania, 

 ' edentula, 

 ' multibilis, 

 ' radula, 



L. concentrica, 

 ' divaricata, 

 ' carnaria, 

 ' scabra, 

 ' reticulata, 



L. squamosa, 

 ' lactea, 

 ' undata, 

 ' circinaria, 

 ' columbella, 



L. sinuata, 

 ' pecten, 

 ' lutea, 

 ' digitalis, 

 ' srlobularis. 



Donax. Shell transverse, equivalve, inequilateral, the anterior side very 

 short and very obtuse; two cardinal teeth, either in both valves, or in the one 

 only; one or two lateral teeth, more or less distant. Ligament external, 

 short, inserted in the place of the lunula. 



D. scortum, 



' pubescens, 



' compressa, 



' cuneata, 



' deltoides, 



' radians, 



' abbreviata, 



D. granosa, 



' columbella, 



' veneriformis, 



' australis, 



' epidermia, 



' bicolor, 



' vitrata, 



D. triquetra, 



' ringens, 



' rugosa, 



' Cayennensis, 



' elongata, 



' denticulata, 



' cardioides, 



D. meroe, 



' scripta, 

 ' trunculus, 

 ' flabagella, 

 ' cinatinum, 

 ' Martinicensis. 



2. Having no lateral teeth. 



Capsa. Shell transverse, equivalve, close; hinge having two teeth in the 

 right valve, and one entering, bifid tooth on the other; no lateral teeth. Lig- 

 ament external. 



C. laevigata, C. Braziliensis. 



Crassina. Shell suborbicular, transverse, equivalve, rather inequilateral, 

 close; hinge with two strong diverging teeth in the right valve, and two very 

 unequal teeth in the other. Ligament external, on the longest side. 



C. danmoniensis. 



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