U. S. B. F-Doc. 731. 



Plate IV. 



Nv 



BORERS, OR "snails" ^PURPURA H/EMOSTOMA ), THEIR EGG CASES, AND OYSTER SPAT 

 DRILLED BY THEM. BAY TAMBOUR, LOUISIANA. 



[Figurus nntunil .-^izc] 



