66 JOURNAL OF THE [March, 



house these shingles may be seen edgewise. So on the side of 

 an oyster-shell is a series of lines. This is the edgewise view of 

 the shoots, or season-growths. Another factor is this purple 

 spot, or scar, in the interior of the shell. It is the place of 

 attachment of the adductor muscle. Its first place of attach- 

 ment was close up to the hinge. Had it stayed there until the 

 shell had become adult, how difficult would be the task of pull- 

 ing the valves together ! the leverage to be overcome would be 

 so great ; for we must bear in mind the fact that at the hinge 

 end the valves are held by this black ligament, which is, in life, 

 elastic, swelling when the shell opens, and being compressed 

 when the animal draws the valves together. So, with every 

 year's growth, or elongation of the shell, the mollusk moves the 

 place of attachment of the muscle onward, that is, an advance 

 farther from the hinge. As it does so, it covers up with white 

 nacre all the scars that are back of the one in actual use as the 

 point of attachment of the muscle. This you can prove by 

 eating off with nitric acid this covering, and thus exposing the 

 whole life-series of scars, or attachments. 



I have likened the oyster's shoots, or season-growths, to the 

 shingles on a roof. To make the similitude complete, it would 

 be necessary for the bottom shingle on the roof to underlie the 

 whole series, and reach even to the roof-tree, or ridge-pole. 

 Then the second shmgle from the gutter must in like manner 

 underlie all the rest of the series ; so of the third ; and so on 

 with the rest. In this way lie the shoots, or laps, of the oyster's 

 shell. The last one deposited underlies them all, and every one 

 terminates at the channel in the bill — so that this groove in the 

 bill contains a series of transverse lines, each one marking a 

 season, or year. Thus we get really four factors for the solu- 

 tion of the question, " How old is the oyster?" all of which are 

 the outcome of the method or way of making the shell. 



Now for the story of the shell in my hand. This, with 

 another, was given me by an intelligent oyster-raiser at Keyport, 

 N. J., with the question, " How old are they ?" My answer was : 

 " About thirty years." Said he: " You have hit it. In 1855 I 

 planted a bed of oysters on a clean sandy bottom. But they 

 did not do well. Oysters want, at least, a little mud. The next 

 year we took them up for the market ; but they were poor. So 

 we dredged the bed, and did not plant there again. This year 



