I examined it for the first time in Atlantic City on March 29. It was then lying on the floor of the skating rink in such a position that the under surfaces were concealed, and, as the teeth were not visible, I mistook it for a female. Upon its arrival in Washington, however, where it could be examined under more favorable circumstances, it proved to be a male. The following measurements were taken from the fresh specimen: _External dimensions of a specimen of M. europæus from Atlantic City, New Jersey._ Ft. in. Total length (in a straight line) 12 6 Tip of beak to base of dorsal fin (along the back) 7 6½ Tip of beak to base of pectoral fin (along the back) 2 11 Length of pectoral fin along center 11 Greatest breadth of pectoral fin 3¾ Height of dorsal fin (in a straight line) 6 Length of base of dorsal fin 1 2 Breadth of flukes (tip to tip) 2 11 Depth of tail 14 inches in front of posterior margin 8¼ of flukes Tip of beak to angle of mouth 9¾ Tip of beak to eye 1 8¼ Length of eye 1 Breadth of blowhole 4 Tip of beak to right angle of blowhole 1 6½ EXTERNAL FORM AND COLOR. The general form was slender and elongate. The beak sloped gradually from its extremity to the forehead, and there was no constriction separating the beak from the remainder of the head. Behind the blowhole, the outline of the back commenced at a higher level, but immediately curved slightly downward, indicating the position of the neck. The line then rose gradually until the anterior base of the dorsal fin was reached. Behind the fin the outline sloped downward gradually to the flukes. The dorsal fin was relatively small, falcate, and obtusely terminated. The distance in front of its anterior base was three-fifths of the total length. Its posterior margin was continuous with the ridge of the back, which extended to the flukes and terminated abruptly a little anterior to the middle point of the antero-posterior breadth of the flukes. In front of the fin the back was rounded.