NOTES ON THE COMMON LlilPET. 15 



which it did but seldom, the wire was let down on 

 the to]3 of the shell. 



Although, as stated, more of the movements of the 

 animal could be seen in confinement than when at 

 liberty, yet it was found during observations made 

 every morning and evening, and frequently at other 

 times of the day and night, over 61 days, that there 

 was not much difference between the habits of the 

 limpet in the one case and the other. In confine- 

 ment as well as at liberty it generally went out to 

 browse about once in every twelve hours, occasion- 

 ally in about twenty-four hours, and a fe^v times 

 only once in from thirty-five to forty-eight hours. 

 As the exact time when it commenced to move ^vas 

 not always seen, in such cases the time ^vas taken 

 from the last observation, which did not give the 

 exact time or interval between the one move and 

 the other; but it was found that it always corres- 

 ponded closely with the duration of one or more 

 tides. Sometimes it ^^ent out to feed at intervals, 

 of three or four hours, but such irregularities were 

 quite exceptional. With the help of the small 

 gummed tickets I was able to mark every change 

 of position that the animal made, ^vhicli amounted 

 to nine in number during the 61 days. These 

 changes ^vere numbered on the tickets as they 

 occurred, leaving them all before my eye on the 

 glass. From these mai'ks I found that it would 

 return once or twice to the same sj^ot, then change 

 to another, then return back again to ^vhere it had 

 been at first. Sometimes it would settle on the 

 exact spot it had left five or six days before, and 

 once as far back as thirteen days. Generally 

 it settled on the exact spot it had formerly occu- 

 pied, yet occasionall}" it would be a. little to the 

 one side or the other. In most cases it came down 

 on the site from above, and occasionally rested a 

 little before it finally reached it. 



Regarding the functions of the tongue, it 

 is stated that "this instrument is thrust out 



