MORSE: OBSERVATIONS ON LAMELLIBR ANGUS. 
179 
PETRICOLA PHOLADIFORMIS Lamarck. 
Fi^j. 3;}. Ix'uiitli, 47 mill. 
This beautiful shell so much like a Pholas is common on the 
beaches. I have dug it up alive in Salem Harbor in company 
with Pholas crispata and P. trimcata. The animal is white, the 
foot is long, and the creature crawls easily. The syphons are 
Fig. 33. — Petricola pholadiformis Lamarck. A, young; length, 3 mm. 
long, slender, and widely separated to within a short distance 
of their bases; they are much longer than the shell, the branchial 
syphon being the longer, and are very mobile. Short simple 
papillae fringe the opening of the anal syphon; no trace of a 
