Marvels of the Untverse [003 
fishermen they wondered how they could have lived so long without discovering the fact for them- 
selves. 
There is yet another purpose served by the broad and hollow ridges of the scallop-shell—that is 
security. The grooves, it should be noted, of the under-valve fit into the ridges of the upper, and 
vice versa, so that when the inhabitant has determined to close up the two valves their edges are 
inexorably locked one in the other, and there is no chance of them slipping apart, whatever force 
may be brought to bear on them. It is hopeless, therefore, to try to wrench the two valves asunder, 
and the fortress can only be entered either by leverage or boring. The star-fish employs the former 
method : attacking the unfortunate victim in the same way as he does the oyster (see page 605), 
but the majority of the Scallops’ enemies favour the boring process, which does not call for the same 
amount of strength. 
Most Scallops are perfectly symmetrical and have equal valves, but exceptions to this rule are 
of some importance, as they form a large group in the family. These, like the Great Scallop, or the 
SCALLOPS. 
The lower valves of two species in which the sculpturing takes the form of fine concentric grooves and ridges. 
variety shown in the illustration on page 1004, have the upper valve flat and the lower deeply 
curved, so deeply, indeed, that the thrifty housewife has long looked upon them as excellent large 
spoons which Nature has provided for domestic use. 
The Scallop family can also provide some excellent examples of a remarkable feature in shell 
coloration ; that is, the unequal distribution of tint on the upper and lower shells of a bivalve. Take, 
for example, the specimen here given. The outer side of the lower valve of the shell is white, the 
upper, red; and among other instances of this characteristic is that of the Great Scallop, or Clam, 
where the upper shell has red ribs with brown interstices, and the lower is white suffused with pink 
and yellow. No doubt the reason for such coloration is that the upper shell is alone conspicuous, 
and therefore assumes the tints of its surroundings in order to escape notice, while the lower 
is allowed to follow the natural coloration of the species ; but it is wonderful that the mollusc should 
be able to vary, as it undoubtedly can, the colouring of the various parts of its shell. 
There is another point which ought to be mentioned before we leave our subject, and that is 
the Scallop’s possession of ocelli, or little eyes, which lie beneath the outer fringe of its mantle. 
This mantle is double-fringed and borders the whole lip of the shell. In the upper mantle-border 
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