ROCK-BORERS 



1 Rayed Machtera, Mackara Amboyna. 



2 Ridged Rock-borer, Petricola coslulala. 



3 Piddock-shaped Rock-borer, Petricola pholadiformis. 



AND HARD-SHELL CLAMS 



5 Xuttall's Hard-shell Clam, Saxidomus NutlaUii. 



6 East Coast Hard-shell Clam, or "Little Neck," 



Venus mcrcenaria. 



