TELLENS. 283 
bordered with fringes; the gills are unequal on 
both sides. The siphons are very much lengthened, 
separate, and diverging, returning into a fold of the 
mantle; their orifices but slightly fringed. Not- 
withstanding the gaiety of the shell, the animal in 
this family is always arrayed in white, “ simplex 
munditiis;” differing in this respect from Donaz, 
the inhabitant of which usually rivals its shell in 
gorgeousness of hues. 
About seventy species are enumerated, which 
live at various depths, chiefly in the warmer seas ; 
their habits closely agree with those of the preced- 
ing family. They are much preyed upon by the 
carnivorous Gasteropoda, as Strombus, Buccinum, 
&e., their thin shells exposing them with more 
than ordinary ease to the depredations of those 
boring Mollusks. 
GENUS PSAMMOBLIA. 
The shell in this lovely genus is more or less 
oval, the breadth commonly being double the 
length; the surface smooth, or delicately striated, 
and clothed with a thin epidermis. The hinge is 
composed of two cardinal teeth in one valve, re- 
ceiving one from the other; the ligament is pro- 
minent. 
The animal is white, with the mantle open, and 
slightly fringed; the very long siphons are marked 
along their length with lines of cilia, and fringed 
at their orifices. The foot is large and tongue- 
shaped. 
These Mollusks have the habits common to all 
these allied families. They live, as their name 
