Eduard Hendrik von Baumhauer

“ In this case, in fact, the gallery is approaching either the surface of the wood or a neighboring gallery; a teredo is never known to destroy the work of another; that, moreover, would not serve him, for, even should he perforate the woody division between them, he would drive against the calcareous tubes, which, being scarcely less hard than the valves themselves, cannot be attacked by them. Whenever the teredo encounters an obstacle, he simply turns aside ”

“ Although confined during its entire life to the dwelling which it has itself constructed, the teredo still has a strongly-developed muscular system. It is evident, moreover, that he uses all his muscles, excepting only those which serve to move the siphons, more or less directly, in the perforation of his galleries.
The first system of muscles is that which one finds in the mantle. That organ is provided through its whole length with longitudinal and
transverse muscular fibres. ”

“ Just so soon as a point of surface of the wood is uncovered, be it ever so small, the teredo, still microscopic, penetrates into the interior. Covering wood with sheets of copper or zinc, or with nails, is a too expensive process, and only protects the wood so long as they form an unbroken surface. ”

“ When these animals, to which sailors and the inhabitants of our coasts give the name of Pustules of the Sea, or Sea-Thorns, multiply to such an extent on the surface of wood that their disks touch, without leaving the least vacant space, the natural consequence is, that the young teredo cannot find any place where it can attach itself, and hence it is impossible for him to penetrate the wood. ”

“ There are the longitudinal and transverse muscles through the whole length of the mantle, a true sphincter (Fig. 10, c) at the base of the siphons, a muscular organ which receives and covers a part of the valves, two adductor muscles for the movement of bringing the valves together, and a foot provided with a suction-disk and susceptible of extension and retraction—truly a profusion of motive organs which one would not expect to find in an animal which passes its entire life in a narrow canal which it can never quit. ”

“ Although we do not know with any certainty if, among exotic woods, there may not be found those which will resist the teredo, we can affirm that hardness is not an obstacle which prevents that mollusk from perforating his galleries; the ravages observed in the wood of guaiacum and mamberklak prove this. ”

“ When the pieces of wood treated with oil of paraffine were taken from the water in 1862, after a sojourn of more than two years, or rather during three summers, traces of the teredo were found in the pieces of oak, but not on those of red fir; but when examined in November, 1863, fully-developed teredos were found everywhere, in the fir as well as in the oak, in the pieces whose surfaces had been removed by the adze, but not more than in those which had not been submitted to any examination. ”

“ The size of those small teeth varies according to the position they occupy: those which are in the vicinity of the hinge-border are the smallest, those which are on the outer edge are the largest. And, as the part of the shell which is nearest the hinge is the earliest formed, in fact the only portion which exists at a very early period, it follows that the average dimension of the teeth increases with the size of the shell, that is to say, with the growth of the animal. ”

“ In all the pieces were found, here and there, galleries of the teredo, but always in small numbers; in sawing the wood, it was found that the injuries were invariably in those parts where the color showed that the oil had not been able to penetrate. Although, as far as is known, no effort has been made elsewhere to preserve oak from the teredo, the commission places great value upon experiments with this wood. In fact, for many marine works, oak cannot be replaced by any soft wood which absorbs creosote-oil easily. ”

“ The teredo does not bore out his galleries, but he hollows them out with an action analogous to that of a file, by means of the thousands of cutting teeth with which its valves are armed. If the teeth do not break away rapidly, it is due to their wedge-like form and to the oblique direction of the planes which bound each of these wedges. Moreover, as the animal grows, new rows of teeth are formed, so that the rows which have served in youth are no longer of any use in more advanced age ”

“ In the variety of teredo described by us, we have never observed the formation of two openings surrounded by calcareous matter, situated side by side, like an eight placed sidewise, ∞, [2] and serving as a passage for the siphons, as described by Deshayes.
The calcareous tube, once formed, constitutes for each teredo his own abode, where he isolates himself from his companions, and has nothing to fear from their close proximity. ”

“ One never sees a teredo pierce the tube of another. The tubes make their way side by side, 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. ”

“ The teredo continues to grow in the wood; while the gallery which it forms presents near the surface a diameter of only one-quarter to half a millimetre, it enlarges little by little, until it reaches a diameter of five millimetres and more; as regards his length, and consequently that of the tube which incloses him, we have sometimes found it to be thirty to forty centimetres. He never goes upward more than half-way between the flow and ebb of the tide ”

“ The form of the end of the cavity, that of a regularly rounded basin, suffices to prove that the valves of the shell are placed every instant in contact with a different spot. The foot displaces itself, little by little, so as to give a rotating movement to the shell, and at the same time to all that part of the body beyond the shell, even as far as the palettes. When the torsion thus produced becomes excessive, the foot loosens its hold, and the body returns to its former position. ”

“ An equally favorable and decisive result was obtained from the pieces of fir creosoted at Amsterdam. Notwithstanding they had been exposed in the sea since July, 1860, during five consecutive summers, nothing could be discovered which resembled the galleries of the teredo: one of the pieces, at a point where the color of the wood indicated an insufficient penetration of the creosote-oil, showed a very slight worm-eaten appearance; but the absence of the calcareous deposit, and the whole character of the opening, indicated clearly that it should be attributed to some other animal than a teredo. ”

“ The development of the eggs progresses very rapidly; in four days they pass out of the embryonic state, fully equipped for living in wood. Toward the end of June, Kater observed them in large numbers on the surface of wood, and by the 15th of July he found them in the interior in the form of perfectly-developed teredos. Even in the month of December, but no later, he saw young teredos enter into pieces of wood placed by design in the water ”

“ 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 ”

“ In a third phase of development the bivalve shell is formed, the foot appears on the outside, the vibratile cilia form a sort of crown, and the embryo thus possesses the faculty of locomotion as well by creeping as by swimming. ”

“ There are two adductor muscles. The first and largest is already well known; it has been described by all writers who have made the teredo an object of study. It extends (Fig. 11, m) between the two valves in the form of a muscular mass, relatively quite large, and occupies about two-thirds of the length of the shell and one-third of its width. ”

“ The experiments were made the first year in the ports of Flessingue, Harlingen, Stavoren, and Nieuwendam, and afterward in the ports of Nieuwe-Diep and Stavoren. The woods employed were oak, red fir, ordinary fir, and Pinus sylvestris, generally in pieces one metre long by two or even three decimetres square. These blocks were prepared in different ways, and care was taken to place by their side blocks of the same kinds of wood without any preparation as counter-proofs. ”

“ Here (Fig. 6, e e) the lines of growth form partitions between as many rows of small, sharp,wedge-shaped teeth. Each of these teeth has two rectangular faces on either side of two small triangular faces inclined toward each other (Fig. 8) ; its cutting edge is placed in the direction of the axis of the animal. ”