Fumtions of the Livinoria Terebrans, 327 



tacks by frequent pitching ; and other vessels by copper-sheath- 



The second point of inquiry is, How is the food procured ? 

 and this leads us to the examination of the peculiar process by 

 which the limnoria is distinguishtd, namely, its boring. In 

 commencing its ravages on an entire piece of wood, it would 

 seem that the limnoria fixes first upon the soft parts, situated be- 

 tween the harder annual layers. After effecting for itself a 

 lodgement within the wood, by excavating a hole somewhat 

 larger than is sufficient to contain its body, it directs its work- 

 ings upwards, at an angle of about 45°, and keeps, in preference, 

 in the course of the soft layer into which it bored at first. In 

 this process, the mandibles seem to be the most effective tools. 



When a section is made of a piece of wood, filled with lim- 

 noria, recently taken from the sea, and the wood is immersed in 

 salt-water in a glass vessel, of a form convenient for its close ex- 

 amination, if care shall have been taken to cut, so as to expose 

 some of the holes just at their internal extremities, the animal 

 may occasionally be detected in the act of boring. It is seen 

 to apply the mouth to the surface of the wood, and slowly to 

 rotate its body by the aid of its legs, placed against the walls of 

 its gallery. I have found it impossible to perceive the action of 

 the jaws or mandibles during the operation. It seems to be ne- 

 cessary to its working that the hole should be filled with salt- 

 water. It has been already stated that the animal bores up- 

 wards ; but very often its galleries are horizontal, and sometimes 

 perpendicular, either upwards or downwards, but chiefly in the 

 former direction. Their course is, for the most part, tortuous. 

 They are cylindrical, or very nearly so. Their diameter varies 

 from g^^th to ^T;\h of an inch, and is nearly the same throughout 

 the whole length of the hole ; which would seem to indicate 

 that, as the animal increases in size, it leaves its old workings 

 and begins new ones. Their walls are as smooth as the surface 

 of a piece of wood of the same kind, which has been cut by a 

 sharp knife. They have no visible lining of any kind. Their 

 terminations are seldom more than two inches from the surface 

 of the wood. The hard ligneous layers of the circles of annual 

 growth, are much less generally perforated than the softer lay- 

 ers ; so that, in a piece of timber much destroyed, (such as is 



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