MUSSELS AND PECTENS 49 



"As time goes by, they enlarge their shells on 

 whatever side there is the most room, and so when 

 they get to be old, some are long and narrow, some 

 flat and round, while others are cramped or half 

 doubled up. 



"As soon as they settle down they close up the 

 finger-hole, for they have no more need to spin an- 

 chor threads; but you can always see on the shell 

 the place that used to be open. You can tell their 

 shells, even if they are old and broken, for they 

 always color the part next to the hinge with a rich 

 purple that never fades or washes out. 



"But good-bye, now, for I must go, or the tide 

 will leave me high and dry. When I am dead you 

 may find my shells washed up on the beach. If you 

 do find them, please put them in your cabinet with a 

 proper label; and whenever you look at them, think 

 of me, and of my little story about the pectens." 



Lima dehiscens^ Conr., the File-shell, is 

 shown in Figure 24. It resembles a pecten, 

 but the ears are small. The animal can 

 swim freely. The shell is pure white, deli- 

 cate, oblique, the valves gaping on one side. 

 The sculpturing is fine and straight, like 

 the teeth of a file. It is sometimes thrown up by 

 storms, and is also found attached to seaweed. Some 

 specimens grow to a much larger size than is indi- 

 cated by the figure. It occurs from Monterey south- 

 ward. 



