WHELKS, ETC. 183 
artist. It became a matter extremely desirable to 
preserve the mussels, and it seemed practicable to 
extirpate the Buccinum. But after we had picked 
up and destroyed many barrels of them, their 
extirpation was at length given up as a hopeless 
task. The mussels were thus abandoned as their 
prey, and in the course of the third year’s opera- 
tions, so successful had the ravages of the Buccinum 
been, that not a single mussel of a large size was 
to be found upon the rock, and even the small 
kind which bred there, are now chiefly confined to 
the extreme points of the rock, where it would 
seem their enemy cannot so easily follow them.” 
The mode in which the Purpura actually per- 
forms the operation, has been described by Mr. Spence 
Bate from observation. ‘The Whelk,’’ he observes, 
*“* attacked the Mussel, but it bored where there 
was no epidermis. I pulled it off, and turned the 
Mussel upside down (the other valve having more 
epidermis upon it), but in a short time I returned, 
and found that the Whelk had turned over the 
Mussel, and had resumed its operation at its old 
bore. This I did twice or thrice, with the same 
result. Giving up the idea of its boring at any 
other point, I next thought I should like to see 
how it managed to devour its prey. For this pur- 
pose I divided the muscles of the Mussel, so that 
the valves parted, so as to enable me to observe 
the work of gormandizing as it proceeded, but to 
my surprise, the-animal gave up all idea of boring, 
when there was an easier method of obtaining food, 
and so passed its proboscis between the valves. 
I think this shows that the Whelk, when it attacks 
its prey, seeks out for the part most suitable for its 
operation, and I believe invariably chooses a point 
