On the 13th of Dec. 1889 a great Sun-fish was washed ashore at Ameland. Through kind intervention of the mayor of the island, D. W. J. baron van Heeckeren , the gigantic fish was sent up to the Leyden Museum, where it arrived a few days afterwards in a satisfactory state. As far as I know of, it is one of the largest specimens of Ortliragoriscus. The dimensions are as follows: Distance from the tip of the mouth to the extremity of the tail M. 2.23 Distance from the root of the dorsal fin to the root of the anal fin, measured at the anterior part of the fins M. 1.40 Distance from the root of the dorsal fin to the root of the anal fin, measured at the posterior part of the fins M. 1.12 Distance from the top of the dorsal fin to the top of the anal fin M. 2.80 Distance from the tip of the mouth to the anterior part of the root of the dorsal fin ... M. 1.45 Distance from the tip of the mouth to the anterior part of the root of the anal fin. . . . M. 1.53 Breadth of the dorsal fin measured at the root. M. 0,42 Breadth of the anal fin measured at the root. . M. 0.35 Distance between the tip of the upper jaw and the anterior part of the root of the pectoral fin. M. 0.67 Distance between the tip of the upper jaw and the centre of the eye M. 0.30 Horizontal diameter of the eye M. 0.08 5 Vertical diameter of the eye M. 0.07 Greatest thickness measured between the pectoral fins M. 0.45 Thickness measured just behind the pectoral fins. M. 0.42 Breadth of the pectoral fin measured at its root. M. 0.21 The weight of the liver amounted to 68 kilograms, whilst the ovarium (our specimen is a female) weighed 4.5 kilograms. The diameter of the best developed eggs varied between 0.42 m.m. and 0.45 m.m.