20 
THE LIVING WORLD. 
Mollusca , a term meaning without shell , i. e., soft, fleshy, from the Latin mollis , 
soft. The term is misleading, for if literally correct, man himself would be 
so classed. A better definition, if not a more suitable term is, an order of 
invertebrates, or creatures having no backbone, and apparently without joints, 
with feet and locomotive powers usually located at or near the head. This 
definition needs qualification in that several of the species are protected by a 
shell covering, such as the oyster, mussel, snail, nautilus and others, but this* 
protection in most cases may be cast and is therefore not a part of the animal 
itself. 
Of the order of Mollusca, or Mollusks, there are two subdivisions, known 
as the Mollusca Ordinaire , or common mollusks, and the Anthoid Mollusks ; in 
the former being four, and in the latter five classes, which are again divisible 
into no less than fifty species, some of which we shall notice. 
So widely different, not only in appearance, but habits as well, are the' 
several species of mollusks, that while some are most useful, as articles 
of food for man, and others yielding pearls 
of great beauty and value, there are not a 
few species that by their wonderful labors 
become sources of extreme danger, and 
more than counteract the good of their 
more useful cousins. 
The Teredo, or ship worm , which be¬ 
longs to this order, penetrates the largest 
ship timbers, and with constantly vora¬ 
cious appetite, and increase of numbers, 
not infrequently reduces them to a mere 
shell, and imperils the ship’s safety. 
The teredo , though called the ship- 
worm , from the siphons which compose its 
soft part, is really a bivalve. It is as de¬ 
structive to wood-work as the Termite Ant, 
but on the other hand its method of boring 
is said to have suggested to Brunei the 
idea and the method of tunnelling the river Thames. Thus it appears that 
while the sluggard is admonished to go to the ant, most creatures, even those 
too insignificant to be of much promise, may have practical lessons to teach 
as well as the equally valuable lesson of religious morality. 
The Lithophytes, or stone borers , not only work their way into solid rock, 
eroding a passage by constant application of a rough sole with which they are 
provided, but often concentrate in such numbers, and become so densely inter¬ 
twined and strongly attached to the rocks, that they occasionally form reefs 
large enough to block up the entrance to harbors. They are fortunately not 
widely distributed, being confined to the Torrid Zone, and most common in the 
Pacific Ocean. 
The Coral Workers, known to science as polypes, and also as anthozoaires , 
or flower animals, though so small as to be imperceptible to the unassisted eye, 
perform more surprising wonders and create more deadly perils to ships. Their 
amazing fecundity, and even more remarkable adaptation, enables them to 
perform the most prodigious labors, in comparison with which man, with all his 
teredo, or ship worm (Teredo fatalis ). 
