19 
are strained from it and the gills have absorbed its oxygen. 
From the other end of the shell the white muscular foot is seen 
protruding. 
Another little shell having the form of Donax, is Tellina 
2 teneraSay. It ismuch more fragile than Donax, 
wider, and the edges of the valves are smooth, not 
crenulated. The color is generally a delicate pink 
Telli: ccsera. OF deep rose color. 
Macoma baltica Linné, another member of the Tellinide 
or Tellea family, is larger than the last, and rounder in out- 
line. sees is either white or pink, and is covered with a very 
thin brown epidermis, usually worn off 
except around the lower edge. 
Macoma tenta Say is longer and nar- 
rower than ZT. tenera and white or yel- 
lowish. These tiny species are our 
iene Macoma baltica, northern representatives of the family 
to which that beautiful white, pink-rayed, Tellina radiata of 
Florida belongs. 
The Soft Clam or Sand Clam, Mya arenaria Linn. is by 
far the choicest of our food clams; but all its tenderness and 
sweetness are concealed beneath a rude and un- 
») polished exterior, as the novelists say. Mya be- 
~ longs to that class of bivalves which have the lig- 
Mac sen znta. ament for opening the shell inside or below the 
hinge-line, instead of outside—an important difference from a 
mechanical point of view, for in pulling the valves shut, the 
ligament or cartilage is compressed in these forms, whilst in 
those with an external ligament, such as Venus, Solen, Tellina, 
