1907.] STUDIES ON THE LIAIPET. 857 



P. Fischer (7) says that young ones wander only when uncovered. 

 Bouchard-Chantereaux (1) says that it makes its excursions just 

 after the tide goes out, Lloyd Morgan (11) that it wanders chiefly 

 as the tide leaves it, and as the tide returns. Lloyd Morgan and 

 Roberts (13) are of opinion that it does not move about when 

 submerged. 



The observations recorded in this paper show that limpets 

 above 20 mm. or so in length do not wander when uncovered by 

 the tide. Smaller limpets, however, may wander even when 

 uncovered, but also when they are covered by the tide. I believe 

 that the difterences of opinion regarding this point arise from the 

 fact that the habit of fixity becomes established only when the 

 shell has reached a length of 10-15 mm. Dr. Robertson's 

 observations seem to me to be the fullest and most satisfactory 

 of all. He found that limpets go out on the flow of the tide, 

 sometimes for two consecutive tides, sometimes alternately. 

 Limpets in captivity had very much the same habits, going out 

 to browse about once in the twelve hours. 



The gi'eatest distance from which a limpet has been known to 

 return to its " home" is three feet (Davis, 3). 



The seat of the limpet's marvellous sense of direction is quite un- 

 known, and the accuracy with which it retui'ns to a definite spot is 

 very astonishing. Several observers (Lukis, Roberts, Hawkshaw, 

 Robertson, Morgan) have noticed that the edge of the shell is 

 often accurately adjusted to the irregularities of the rock, or to 

 barnacles, round about the " home." I haA^e recorded in this 

 paper one or two other instances of the same thing. 



A.S to how long a limpet may stay in one spot, Lukis records 

 the fact that five limpets observed in 1829 were found in the same 

 position several months after ; and I have had one or two under 

 observation for six months which kept exactly to the same spot. 



I give here some observations made in 1906 at Kames, Kyles of 

 Bute, on a number of limpets in their natural habitat. Each of the 

 limpets had a distinctive mai-k filed on its shell, so that no mistake 

 as to identity might be made. All the measurements were taken 

 while the limpets were uncovered by the tide. The first table 

 refers to four limpets, ranging in size from 34 mm. to 44 mm., 

 which grew close together on a ledge of rock near high-water 

 mark. 



Table I. 



