86 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [380] 



rows are nearly round, and of all sizes up to about a sixteenth of an 

 inch in diameter, and they go into the wood at all angles and are 

 usually more or less crooked. They are often so numerous as to reduce 

 the wood to mere series of thin partitions between the holes. In this 

 state the wood rapidly decays, or is washed away by the waves, and 

 every new surface exposed is immediately attacked, so that layer after 

 layer is rapidly removed, and the timber thus wastes away and is en 

 tirely destroyed in a few years. It destroys soft woods more rapidly 

 than hard ones, but all kinds are attacked except teak. It works 

 chiefly in the softer parts of the wood, between the hard, annual lay 

 ers, and avoids the knots and lines of hard fiber connected with them, 

 as well as rusted portions around nails that have been driven in, and, 

 consequently, as the timbers waste away under its attacks, these 

 harder portions stand out in bold relief. Where abundant it will 

 destroy soft timber at the rate of half an inch or more every year, thus 

 diminishing the effective diameter of piles about an inch annually. 

 Generally, however, the amount is probably not more than half this, but 

 even at that rate, the largest timbers will soon be destroyed, especially 

 when, as often happens, the Teredos are aiding in this work of destruction. 

 It lives in a pretty narrow zone, extending a short distance above 

 and below low-water mark. It occurs all along our shores, from Long 

 Island Sound to Nova Scotia. In the Bay of Fundy it often does 

 great damage to the timbers and other wood- work used in constructing 

 the brush fish-weirs, as well as to the wharves, &c. At Wood s Hole it 

 was formerly found to be very destructive to the piles of the wharves. 

 The piles of the new Government wharves have been protected by 

 broad bands of tin-plate, covering the zone which it chiefly affects- 

 North of Cape Cod, where the tides are much greater, this zone is 

 broader, and this remedy is not so easily applied. It does great dam 

 age, also, to ship-timber floating in the docks, and great losses are 

 sometimes caused in this way. Complaints of such ravages in the 

 navy-yard at Portsmouth, New Hampshire, have been made, and they 

 also occur at the Charlestown navy-yard, and in the piles of the wharves 

 at Boston. Probably the wharves and other submerged wood- work in 

 all our sea-ports, from New York northward, are more or less injured 

 by this creature, and, if it could be accurately estimated, the damage 

 Avould be found surprisingly great. 



Unlike the Teredo, this creature is a vegetarian, and eats the wood 

 which it excavates, so that its boring operations provide it with both 

 food and shelter. The burrows are made by means of its stout mandi 

 bles or jaws. It is capable of swimming quite rapidly, and can leap 

 backward suddenly by means of its tail. It can creep both forward 

 and backward. Its legs are short and better adapted for moving up 

 and down in its burrow than elsewhere, and its body is rounded, with 

 parallel sides, and well adapted to its mode of life. When disturbed 

 it will roll itself into a ball. The female carries seven to nine eggs or 

 young in the incubatory pouch at one time. 



