Peter Martin Duncan

“ In favour of the theory of the simultaneous life of the host and the parasite, the theory of the growth of the Algæ in recent times must be advanced and the presence of sea-water and of animal tissue of a low vitality assumed. In addition there is the fact that a portion of a Brachiopod included in a sandy matrix within the coral, and not continuous with coral-structures, contains the tubes. Moreover the crystalline mass of the interstices of the coral, although it holds mechanically abundance of spores, does not present tubes or any evidence of growth. ”

“ Tube may be compared with tube in all its parts; but fossilization has produced appearances in the spores and conidia which suggest distinction between the recent and the fossil kinds of Algæ. Nevertheless the general character of the re- productive resting spores and the conidia arising from the vegetative part of the organism remain much the same. The large tubes in the palæozoic coral and Brachiopod, or whatever else Calceola may be, would at first sight indicate a different species of parasite from those which formed the smaller penetrations ”

“ Usually no origin or ending of the tubes can be seen; but in a few instances their commencement in dark spots at the margin of the coral-wall can be readily seen (fig. 6) . These spots are either not much larger than the tube, or are very much bigger, and are filled with a mass of globules with whose exterior the tubes seem to be continuous. Occasionally small dark pigment-masses with a definite globular shape are in contact with one end of the tubes (fig. 14) . The large masses are probably the remains of resting spores or oospores; and the others are conidia (fig. 3) . ”