6o Shell Life 



rocks, and other submerged objects, and is not un- 

 reasonably — though quite inaccurately — regarded by 

 the 'long-shore folk as the 3^oung of the true Oyster 

 iOstrea). It is not even closely related to the true 

 Oyster, nor is it edible. It is by no means an easy 

 task to persuade fishermen that these are not young 

 oysters, but the quickest method of convincing tliem 

 is to prise off the Saddle-oyster and exhibit its under- 

 side as shown in our figure. It is then seen that 

 there is a pear-shaped orifice in the lower valve 

 through which an attachment plug passes and fixes 

 the Saddle-oyster to its chosen support. No genuine 

 Oyster is attached in this way, nor has it a hole in 

 its shell. The Common Saddle- 

 oyster is about 2 inches across 

 when full - grown, variable in 

 outline, but more or less circular. 

 , ^ , ,, It is never very thick, but varies 



Side view of Saddle-oyster, ^ ^ . 



showing mode of attach- iutliis rcspcct accordiug to age. 



""^"^ Outside it is dull white in colour, 



or tinged with yellow, pink, or brown ; within it 

 is polished and opalescent. The lower valve in its 

 growth follows the modelling of the surface to 

 which it is attached, whether that be the smooth 

 rounded stem of a huge seaweed, the rough sur- 

 face of the rock, or the ribbed shell of a scallop. 

 The upper valve, of course to a less degree, follows 

 the shape of the lower. Normally the lower valve 

 is flat and the upper one convex. There are no 

 liinofe-teeth as in the Nut-shells, thoup^h there is 

 a half - moon shaped pad of cartilage to keep the 

 valves apart when the single muscle is relaxed. 

 The plug by which the shell is fixed to its support is 



