38 LINN^AN GENERA. 



six inches deep in the sand, into which they penetrate with great facility, 

 their residence is known by a small dimple on the surface. In some 

 places they are used as food. 



Genus 6._TELLINA. 



Animal a Tethys ; shell bivalve, generally bent at one end ; 

 in the fore-part of one valve a convex, of the other a concave 

 fold ; hinge vvdth usually three teeth, the lateral ones smooth 

 in one side. 



There are three families of the Tellinfe : ovate and thickish,* ovate 

 and compressed,** suborbicular.*** 



Tellina Fahula The obliquely-striated Tellina. 



Shell very thin, pellucid, and oval, generally white or yel- 

 lowish, and darker towards the umbo; which is nearly cen- 

 tral, pointed, and turned a little to one side ; the anterior 

 side slopes to an obtuse point ; the posterior side is large 

 and rounded ; hinge furnished with three teeth in one valve 

 and two in the other ; one valve obliquely striated. 



Tellina Donacina. — The Donax-like Tellina. Plate 

 V. fig. 6. Suboval, flattish, much sloping on the anterior 

 side, semi-striated, and semi-pellucid; hinge with two teeth 

 in one valve, and one in the other; pale yellow, longitudinally 

 radiated with pink ; half-an-inch long and three-fourths of 

 an inch broad. Inhabits the coasts of Britain. 



The TeUinae inhabit the ocean, rivers, and lakes. Those of the ocean 

 lie buried in the sludge, near the shore, and make two apertm-es in the 

 sand ; when the tide has receded, they may be easily found by looking 

 for these marks. 



Genus 7— CARDIUM. 



Animal a Tethys : shell bivalve, nearly equilateral, equi- 

 valve, generally convex, longitudinally ribbed, striate or 

 grooved, the margin dentated ; hinge with two alternate 

 teeth in the middle, near the beak ; one of them commonly 

 incurved ; and larger remote lateral teeth on one side, each 

 locking into hollows in the opposite valve. 



Cardium edule. — The Edible Cardium. Plate V. fig. 

 7. With about twenty-six antiquated longitudinal ribs ; of 



