Formation of Calcareous Tubes round the Siphons of Teredo

Abstract

AT the beginning of June 1926 a quantity of wood heavily infected with Teredo (probably all Teredo norvegica), taken from the experimental rafts moored near the Plymouth breakwater, was placed in one of the tanks in the Plymouth laboratory. It was left undisturbed for almost four months, and when examined at the end of September was found covered with fæcal deposits consisting of wood fragments cut away by the shell valves of Teredo and passed out by way of the exhalent siphons. These deposits were, on the average, rather less than half an inch thick, and when they were washed away there were revealed, projecting from the wood, great numbers of fine calcareous tubes, which on closer examination proved to occur always in pairs and to project from the openings of the burrows formed by the shipworms. Plainly the tubes had been formed around the siphons of the Teredo. They were of varying length, depending presumably on the thickness of the deposits, the longest being some two-fifths of an inch. The general appearance of the wood is shown in Fig. I.