Attention was drawn to the statements made on the position of peculiar comb-like fringes on the branchiæ of the basking shark by Gunnerus, Pennant, Low, Mitchell, Foulis, Brito Capello, Cornish, Steenstrup, Pavesi, P. & H. Gervais, Percival Wright, and Allman, and to the structure of these fringes by Hannover and MM. Gervais. The author then proceeded to give a detailed description of the structure of the plates forming these fringes from a specimen presented to him by the Rev. M. Harvey of St. John's, Newfoundland, the general summary of which is as follows: the whole periphery of a plate consisted of a hard unvascular dentine, the tubes in which were very distinctive; in a considerable part of the shaft these tubes arose from a single central pulp cavity, but in the semilunar attached base of the plate the single central cavity did not exist, but was replaced by a set of anastomosing vascular canals, which collectively represented a pulp cavity, and which gave origin to numerous characteristic dentine tubes.