548 THE POPULAR SCIENCE MONTHLY. 



and cross each other in every direction, but, be the wood ever so worm- 

 eaten, there always remains a woody wall, often very thin, it* is true, 

 between two adjoining tubes. 



The very existence of the adult teredos seems dependent upon the 

 wood. Withdrawn from their galleries and placed in sea-water, they 

 could be kept alive by Kater scarcely more than three or four days. 

 Left in the wood, but taken out of sea-water, they would die within 

 twenty-four hours. Deprived at the same time of contact with wood 

 and sea-water, they perished at the end of one or two hours. In damp 

 wood, that is, wood soaked with salt-water, their existence is prolonged 

 somewhat. Wood and sea-water are, then, both necessary. If these 

 two conditions of existence are furnished them, one can, Kater assures 

 us, keep them alive during several months. 



The teredo does not always remain in peaceable enjoyment of the 

 home he has constructed, and the nourishment the water brings to him. 

 He finds himself exposed to the attacks of an enemy, of an 

 annelide to which the late M. W. de Haan has given the 

 name of Lycoris fucata (Fig. 13). In our day, as well as at 

 former epochs, this annelide is constantly found wherever the 

 teredo exists. His eggs and embryos are met with in the 

 midst of those of that mollusk. 



Kater has remarked that the adult annelide, leaving the 

 muddy bottom, where he has hibernated, and in which the piles 

 are driven, climbs along the surface of the wood toward the 

 opening made by the teredo ; there he sucks away the life and 

 substance of his victim ; then, slightly enlarging the aperture, 

 he penetrates and lodges in place of the teredo. Later the an- 

 nelide reappears and seeks for new prey. All the early writers 

 on this subject state that they have found this annelide in wood 

 at the same time with the teredo. It is remarkable that a 

 Flo 13 similar annelide, and perhaps the same, has been found in the 

 cavities hollowed out in stone by the pholades. 

 It is important that it should be generally understood that this an- 

 nelide is not only harmless, but renders the greatest service in devour- 

 ing the wood-destroyer. It is a narrow annelide, ten to fifteen centi- 

 metres long, provided on his sides with a great number of small feet 

 terminated with a point and garnished with hairs and showing in front 

 a pair of strong upper jaws, horny and sharp, and lower jaws bent 

 backward in form of hooks and carried outside by the aid of the lower 

 lip, which is developed somewhat like the finger of a glove turned 

 backward. Behind the head are four pairs of tubular-formed gills. 

 With these weapons the annelide pursues and devours the teredo. 

 The observations of Kater teach us that he is generally found in 

 the empty galleries with the remains of the teredo ; sometimes even 

 he is seen as if clothed with the integuments of the teredo, while he 

 is occupied in ransacking his intestines. Once Kater had the rare 



