192 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Fig. 44. — Mya arenaria Linnfi. 
few in number (Fig. 44, a) ; the valve is very long, and the foot 
is long and narrow as shown in the figure. 
SAXICAVA RUGOSA Lamarck. 
Fig. 45. Length, 26 mm. 
The syphons are united nearly to their ends; they occupy the 
entire end of the shell. When first protruding the openings are 
nearly on a plane, the branchial syphon slightly the longer. 
As they continue to expand the branchial syphon becomes 
longer and in some specimens the opening of the anal syphon 
stands nearly at right angles to the axis of the tube and turns 
dorsally. The color is orange or brownish red. The sheath 
enclosing the tubes is roughly marked with a tortuous wrinkled 
periosteum. The papillae are translucent and crowded around 
the openings — a perfect brush, in fact. The papillae are truncate 
and each papilla has an orange-colored line in the center. In 
the young the foot is long, slender, and in constant activity. The 
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