52 THE ZOOLOGIST, 
In the tube of the Teredo, and also in the tubes of Pholas, as 
the learned Jesuit, Bonanni, discovered so far back as 1684, an 
annelid (Nereilepas fucata) often occurs, and some observers men- 
tion that it performs the part of keeping the mollusks in check— 
in short, that itis a destroyer of Teredo. So far as known there is 
no foundation for this view. It is found that the same species of 
annelid frequents, along with the common Hermit-Crab, the 
shells of the Great Whelk, not for any predatory reason but 
simply as acommensal. The association of annelids with other 
forms in tubes or elsewhere is extremely common; indeed, many 
are found only in this association, but it is not for the purpose 
of preying on their neighbours, though the bodies of their hosts 
in many cases are softer than those of Teredo, and their own jaws 
not less formidable than those of Nereilepas. They are commen- 
salistic forms or messmates—that is, dwell in association with 
other animals, each, as the late Prof. Van Beneden, of Louvain, 
tersely said, requiring from his neighbour a simple place on 
board his vessel without asking to partake of his provisions. 
Besides, Nereids have a habit of lurking in holes of any kind, and 
even perforating peat for shelter; and it would be unsafe to 
condemn them from an examination of their jaws, since some of 
those best armed live only on seaweeds. 
But—to return from this digression—it is found that no fewer 
than four British species of T’eredo and several others are occa- 
sionally found in driftwood. In the great and especially the 
warmer oceans almost every piece of timber is attacked, so that 
strict precautions are necessary to protect wooden ships, boats, 
and piles from their ravages. 
The object in life of all the species of Teredo is to bore cease- 
lessly into timber, which they tunnel for the protection of their 
long worm-like bodies, and they line the interior of their tubes 
with a calcareous coat, which helps in some cases to separate 
them from their neighbours. The perforations are generally in 
the line of the grain of the wood, and vary in length according 
to the size of the specimen and the particular species. Thus the 
common Teredo (T'. navalis) has a tunnel from one to two feet in 
length, while that of the giant Shipworm (T. arenaria) extends 
fully a yard, and is two inches in diameter. A curious species 
(T’. corniformis), which burrows in the husks of floating cocoa-nuts 
