370 TELLINID^E. 



Genus II. TELLI'NA *, Linne*. PI. VII. f. 3. 



BODY oval, compressed : tubes slender ; orifices cirrous, or 

 plain. 



SHELL oval, triangular, or oblong, in some species slightly 

 inequivalve, more or less inequilateral, sculptured by con- 

 centric laminae or striae, and occasionally by longitudinal (or 

 partially by oblique) striae ; posterior side flexuous : teeth, two 

 cardinals in each valve ; laterals on either side or on one only 

 of each or one valve, but not always present : inside margin 

 smooth. 



According to Aldrovandus the generic name is de- 

 rived from the quick growth of the shell. He cites 

 Aristotle as his authority; but the expression of the 

 latter (on Ta^iarra ylvovrai reXewu) was used with re- 

 ference to every sort of shell-fish. Mr. William Wood's 

 work, < General Conchology/ published in 1815, con- 

 tains a monograph of all the species of Tellina which 

 were at that time known : it is well executed and pret- 

 tily illustrated. He explained, better than Montagu 

 had done a few years previously, the use of the siphonal 

 tubes, as well as of the linguiform organ usually termed 

 a " foot." As Lamarck observed, the two valves of the 

 same individual are not always perfectly alike ; some- 

 times one valve is more convex than the other. This 

 inequality of size occurs to a certain extent in our T. 

 crassa and T. squalida. The species are exceedingly 

 numerous, both in a recent and fossil state ; according 

 to Chenu there are 220 of the former, and nearly half 

 as many in secondary and tertiary strata. S carles Wood 

 says that " the genus appears as early as the Coral Rag, 

 with some doubtful forms in the Palaeozoic Formations/' 

 Their shells are of an elegant shape, and often variegated 

 by bright-coloured rays and other markings. 



* The name given by Dioscorides to a kind of shell-fish. 



