36 THE SHELL-FISH OF THE COAST. 



purple margin the Indians cut their purple wam- 

 pum (shell-money), the white wampum being ob- 

 tained from the columellar axis of the pear-conch 

 or winkle (Fulgur). The word ' quahog' appears 

 to be a corruption of the plural 

 Poquahock, or, as it is written, 

 ' Poquahauges.' 



Careful observers of the 

 ocean beach will have noticed 

 from time to time little jets of 

 water issuing from scattered 

 holes in the sand; or fre- 

 quently the shallow waters of 

 pools may be observed twirled 

 round into eddies by suction 

 and ejection currents coming 

 from below. The author of this 

 play of water is the sand-clam 

 {Mya armaria), which lies 

 buried a few inches below the 

 surface, whence it communi- 

 cates with the outer world by 

 means of its extended siphon. 

 Through this siphon, which is 

 in reality a double tube, water- 

 currents are passing both in- 

 ward and outward, bringing 

 necessaries to the secluded 



Sakd-clam {Mya arcnaria). ^ . « . 



creature, and carrying from it 

 the waste products. The depth to which the animal 

 burrows will depend closely upon the length of its 

 respiratory siphon. Although it measures but a 



