TELLINA. 377 



many parts of the south of Europe, as will appear from 

 the following epitome of its geographical distribution : 

 Behring^s Straits to Kamtschatka, White Sea, and 

 Nova Zembla to the Black Sea (Middendorff ) ; Finland 

 (Nordenskiold and Nylander) to Kiel Bay (Meyer and 

 Mobius), at depths varying from zero to 60 fathoms; 

 North of France (De Gerville and others) to the coast of 

 Spain (Gay); Toulon (Gay) to Mogador (R. T. Lowe) and 

 Sicily (Scacchi and others) ; Labrador (Brit. Mus.) to 

 Massachusetts (Say) and north-west coast of America 

 (P. Carpenter) . It is also fossil in the Uddevalla and 

 Sicilian pliocene strata. 



This species, so familiar to modern geologists, and such 

 an important test for the discrimination between older 

 and newer or quaternary deposits, was well characterized 

 and figured by Lister. His method of giving the dimen- 

 sions of a bivalve shell is generally correct and that 

 which is now recognized, viz. the length representing the 

 line of growth in the direction of the beaks, and the 

 breadth the extent from side to side. Chemnitz has given, 

 in a vignette in the sixth volume of his ( Conchy lien- 

 Cabinet' (p. 76), a diagram illustrating this mode of 

 admeasurement. The animal has been excellently de- 

 scribed by Bouchard-Chantereaux, who says that some- 

 times the only tube exserted is the branchial one, which 

 the animal stretches out five or six inches in length, with 

 a diameter of only a line, absorbing with" an astonishing 

 rapidity any minute object within its reach. It is essen- 

 tially a hardy mollusk, accommodating itself to all degrees 

 of temperature, and to every kind of water from nearly 

 fresh to the saltest. The typical or original form inhabits 

 the brackish and land-locked Baltic Sea. Loven was in- 

 clined to consider this a degenerate variety of the same 

 species as the T. solidula of Pulteney, but for the pallial 



