66 THE HALL OF SHELLS. 
“You are aware, Tom, with what tenacity 
these abalones cling to the rocks, so they can 
only be removed by taking the little house- 
holder unawares and giving dextrous and sud- 
den knocks.” 
“Yes,” said Tom, “the people here tell of a 
Chinaman who, putting his fingers under one of 
these shells in his attempt to pry it from the 
rock, was held there by the abalone until the 
tide came up and the man was drowned.” 
“This tight huggmg of the rock,” ex- 
plained the doctor, “is accounted for, I believe, 
by the large suckerlike sole of the animal. It 
consists of a rounded disk of muscular tissue, 
which has marvelous power of adhesion and 
brings not a little atmospheric pressure to bear 
upon the shell. Like the limpet, it has a very 
viscous secretion, which is a strong factor in 
holding it to the rock. 
“The apertures along its dome suggest 
round windows high up in some old castle 
wall. They are the openings through which 
the gills of the animal are kept in communica- 
tion with the surrounding water. The earlier 
openings you see are closed—filled up with 
shelly matter—but some are always kept 
open.” | 
As the doctor laid down the abalones, Un- 
