MARINE BIOLOGICAL STATION ON PUFFIN ISLAND. 21 
After sailing down from the port of Bangor, taking: 
surface gatherings on the way, we reached the island in 
good time for the evening low tide, and spent the hours 
till dark collecting amongst the reefs and boulders of the 
South Spit. One of the first objects found on the shore 
was a rather interesting specimen. It was an example 
of the common limpet (Patella vulgata), which, in place 
of being attached to a rock, was sticking firmly to the 
rounded surface of a piece of iron bar froma wreck. The 
limpet was moulded to the surface. Its lower part was 
strongly concave, and the edge of the shell was curved up 
in the middle on each side, and down at each end, so as to 
be able to embrace about half the circumference of the 
cylindrical bar. The animal had evidently grown so as to 
stick closely and tightly to the surface. Now, this would 
not be at all surprising in a coral or an ascidian, or any 
animal which remained adhering to one spot all its adult 
life; but it is remarkable in a case like the limpet, which, 
it is generally supposed, does not remain rooted to one 
spot, but wanders about in search of food. 
Although when we notice limpets on rocks between 
tide marks they are generally fixed and motionless, still 
Prof. J. R. A. Davis has shown that they can loosen their 
hold and crawl over the rocks for some distance. It is 
noticed, however, that when the rock is not very hard, as, 
for example, in the case of the limestone blocks at Puffin 
Island, each limpet occupies a well-marked depression 
exactly its own shape. From this it is clear that the 
animals are not on mere temporary resting places, but 
are in their own ‘‘roosts’’ or homes, to which, if they 
leave them, they return regularly, and which they have 
themselves excavated to a considerable depth and with 
the precise shape of the outline of their own shells. 
So much so that they have to place themselves with the 
