Edible Mollusca of the Oregon Coast.' 



Bv Charles Howard Edmondson. 



IXTRODUCTIOX. 



The ( )re<^"()n coast from the mouth of the Columbia River t<> 

 Cahforuia prcseuts au exceethugly varied contour. Low, flat, sandy 

 beaches ahernate with ruy;',ge(l headlands while the shore line is 

 indented b}' numerous ba}s and inlets of greater or less extent. A 

 numl)er of rivers of considerable size, draining the Coast Range 

 -Mountains, flow into the Pacific within the boundaries of the state, 

 their waters intiuenced by the daily tides for several miles from the 

 ocean. ^lost of them expand into broad, shallow bays near their 

 mouths and .some of them are characterized by extensive mud flats 

 on one or both sides of the channel which make ideal habitats for 

 numerous forms of marine or brackish water organisms. In many 

 places the coast is paralleled by fringing- chains of rocks representing- 

 remnants of a former shore line, now serving- as footholds for such 

 fixed organisms as have l>ecome a(la|)ted to the full sweep of the 

 waves. 



.Vs the physical features of anv coast line determine the types 

 of animals and plants that are distributed along it. so the organisms 

 of the open beaches ditter considerably from those found in the pro- 

 tected ba_\'s and mouths of rivers or along the rock\- shores. 



The habitat conditions in the tidal zone along the northwest 

 coast are such that numerous lamellibranchs have become established 

 and are maintaining- themselves more or less successftdly. Of this 

 number there are about a dozen, besides the western oyster,- Ostrea 

 lurida Carpenter, which have alreadv been recognized, to some 

 extent at least, as tit for human food. 



The following- list of clams and mussels re])resents the bivalves, 

 exclusive of the oyster, of the Oregon coast which have entered into 

 the food economy of the people of the state in some slight deg'ree : 

 Siliqna patula Dixon, commonly known as the "raz(M' clam" : Mya 

 arenaria Linnaeus, the "long neck clam" or "eastern mud clam"; 

 Paphia staminea (Conrad), called the "little neck clam" or "hard 

 clam"; Schizothaerusnuttalli Conrad, localK' known as the "Wash- 



' The investigations reccidcd in tliis paper were conducted wliile tlie writer was a 

 member of the teaching staff of the University of Oregon. 



- For a discussion of the oyster see page 23 of this paper. 



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