e?-^lor^,t•ior.. T'^e :^ost e.-rrcuidant oyster v;as the sriall 0. c-g'ji n.- lf^ia me.-lcpna. , v:}iich c.enr.ely 

 covered t}i.e roc'rs at the niclc.le level of the tidal zone. The oyster is ec.ihle, "out lachs 

 flavor, a:id "because of its sr-iall sir.e is useless for co;-i".erce. 



0. iridescens v/as fouiid in rnanjr Tslaces attached, to l"oc-:s and stones Ijelow lov/- 

 '.•??,ter na,r'C. The largest STseciaen v;as 15 cm. long and 7-8 en. v;idc. The oyster is very 

 flat, v.'ith snail shell cavity; consequeutLy there is "but little neat inside s. rather heavj- 

 shell. The neat is very saltyi aaid, at the time of esiaj.iination, very leaii. Judoiny by the 

 ap-oeaj: Slice, the tissues contained hut little glycogen. 



Ostrea raegodon is a rather large, flat, and round oyster, ahout IS en. long end 

 15 en. v.'ide. The ln;ier surface of the shell is 'blach ejid sli.'^itly irridescent. The oyster 

 cajmot "be eaten rav/, hut is palataole after it is cooked. 0. negodon grov;s finnl;,'- attached 

 to rocks helov.' lovr v/ater, and can "be taken only "by diver. It is douhtful that it could "be 

 esT)loited con-iercially. 



0. chilensis closely resenhles the Atlaiitic oyster (O. virginic a) . It has a deep 

 cuTi-like shell vhich encloses a rather large "body (Fig. 2S) . The imiscle scar is not 

 ■oif;iented. Lil:e 0. virginica , 0. chilensis laay be found grov/ing hoth on rocks ejid on nudd;;r 

 hottor.is. Its distribution erctends iron the Gulf of California to Chile. The oyster 

 arjTjarently thrives on nud bottoms, especially near the river nouths. Extensive bpxs built 

 of shells of this species erist in the Baj-- of St. Miguel (Ensenada de Garachin^ . Wide nud 

 flats of this bay ej-tend over an area of several niles along the shore. At lovr tide, the 

 flats are barren. They v:ere reached by using an Indian "caynga", a dugout canoe v;ith 

 sligLitly flattened botton, v.'hich vfas pushed for severs-l niles along the edge of the flats, 

 and then dragged tov/ard the reef. The oyster bars are surrounded by soft and sticky mid.. 

 The^r all e:d;end at riglit angles to the shore. The bar v/hich I examined in greater detail vfas 

 from Uo to 65 feet uide ajid about 5OO feet long. It represented an accumulation of old oyster 

 shells and in its general appearance, resembled the bars of 0. virginica on juufl.d^- bottons 



( 



Figure 2S Ostrea cldlensis , r^rliicipal edible oyster of the Pacific coast of P?iiai.m. 



On r.ud flats, this oyster forns reefs resenbling those ncx'.e by 0. 

 virginica elong the coast of Gulf of Herico. ~ 



U5 



