TELLTNID.E. 365 



entire aspect of the typical Tellinida" but that its 

 position differs in being very little posterior to the 

 centre of the ventral range, instead of the tubes being 

 (as is more usual in that family) protruded from the 

 posterior angle. He also remarks that the colour of the 

 animal, when killed by hot water, often changes to the 

 various hues of orange, red, and brown, — a condition 

 which prevails more or less in all the testaceous Mol- 

 lusca, and particularly in the bivalves. We must look 

 to the carcinologists for an explanation of this phe- 

 nomenon, remembering the old simile of Aurora : 



" And, like a lobster boil'd, the morn 

 From black to red began to turn." 



This species is the Venus inquinata of Lamarck, V. 

 incompta of Philippi, and, according to him, the Lucina 

 caduca of Scacchi. Deshayes, in his Catalogue of the 

 Bivalve shells in the British Museum, places it, with a 

 doubt, in his genus Cijclina. 



Family XIV. TELLI'NID.E, Latreille. 



Body oval or oblong : mantle fringed with tentacular appen- 

 dages : tubes very long, separate throughout, unequal in length, 

 issuing from a sheath or fold of the mantle : gills unequal in 

 size : palps large : foot tongue-shaped and flexible. 



Shell sometimes inequivalve, triangular, oval, oblong, rhom- 

 boidal, or cuneiform, striated concentrically, and in certain 

 kinds also longitudinally or obliquely: epidermis generally 

 thin, but existing in all the members of this family : beahs 

 incurved, nearly straight: ligament external, placed on the 

 smaller side of the shell : hinge in each valve furnished with 

 two cardinal teeth (one of which is frequently cloven or double ), 

 and, in certain genera and species, with a lateral tooth on 

 each or but one side in either or only in one valve : pallial scar 

 more or less deeply sinuous or indented : muscular scars dis- 

 tinct. 



