480 MANUAL OF THE MOLLUSCA, 
impressions rounded, polished; pallial sinus very large; liga- 
ment on shortest side of the shell, sometimes internal. Struc- 
ture obscurely prismatic-cellular; prisms fusiform, nearly 
parallel with surface, radiating from the hinge in the outer 
layer, transverse in the inner. 
Animal with the mantle widely open in front, its margins 
fringed ; foot tongue-shaped, compressed; siphons separate, 
very long and slender; palpi large, triangular; gills united 
posteriorly, unequal, the outer pair sometimes directed dorsally. 
The Tellens are found in all seas, chiefly in the littoral and - 
laminarian zones; they frequent sandy bottoms, or sandy mud, 
burying beneath the surface; a few species inhabit estuaries 
and rivers. Their valves are often richly coloured and orna- 
mented with finely sculptured lines. 
TeLuInA, L. Tellen. 
Etymology, Telline, the Greek name for a kind of mussel. 
Synonyms, Peroneea (part) Poli. Phylloda (foliacea), Omala 
(planata) Schumacher. Psammotea isoldula) Turt. Arco- 
pagia (crassa) Leach. Tellinodora, Morch. 
Examples, T. lingua-felis, Pl. XXI., Fig. 5. 'T. carnaria, 
Fig. 6. 
Shell slightly inequivalye, compressed, rounded in front, 
angular and slightly folded posteriorly, umbones sub-central ; 
teeth 2.2, laterals 1—1, most distinct in the right valve ; pallial 
sinus very wide and deep; ligament external, prominent. 
Animal with slender, diverging siphons, twice as long as the 
shell, their orifices plain; foot broad, pomted, compressed ; 
palpi very large, triangular ; gills small, soft and very minutely 
striated, the other rudimental and directed dorsally. 
Tellinides, Lamarck. T. planissima, Pl. XXI., Fig. 7. Valves 
with no posterior fold; lateral teeth wanting. 
T. carnaria (Strigilla, Turt.) has the valves obliquely sculp- 
tured; 7’. fabula, Gron., has the right valve striated, the other 
pine T. Burneti, Galton. has the right valve flat; 7’. dunu- 
lata, Pliocene, South Carolina, much resembling it in shape, has ~ 
the left valve flat. 
Distribution, above 800 species. In all seas, especially the 
Indian Ocean; most abuudant and highly coloured in the 
tropics. Low water — Coral zone, 50 fathoms. Wellington 
Channel; Kara Sea; Behring’s Straits; Baltic; Black Sea. 
Fossil, 170 species. Oolites—. United States, South America 
Chiloe), Europe. 
