Meters. Total length from tip of upper jaw to notch of caudal fin, 4.81 along the middle of the back, without, however, following the angle between beak and forehead From tip of upper jaw to fore border of spiracles .53 From fore border of the spiracles to fore border of dorsal fin 2.63 Length of dorsal fin .29 Height of dorsal fin .11 From hind border of dorsal fin to the beginning of the caudal .93 fin From the same point to notch of the caudal fin 1.36 Distance between the tips of the lobes of the caudal fin .91 Depth of the angle of the posterior margin of caudal fin .20 From tip of upper jaw to the angle of mouth .36 From the same to anterior angle of eye .475 Diameter of eye opening .06 From eye to eye over the spiracle .59 Distance between ends of spiracle .08 Length of beak from the forehead .23 Breadth of the beak at the forehead .18 From tip of upper jaw to anterior insertion of the pectoral .80 fin Pectoral fin along the anterior border .51 Breadth of pectoral fin[a] at the insertion .20 Circumference of tail at its narrowest point, just before the .62 caudal fin [a] The pectoral fin rather straight, of equal breadth, and abruptly ending. ORIGINAL DESCRIPTION OF BERARDIUS BAIRDII. The original description of _B. bairdii_ by Doctor Stejneger is as follows: Besides an _Orca_, which is said to visit the rookeries, but of which I have not been able to procure any specimen, or even to see one, there are at least two species of the family _Ziphiidæ_, both undescribed, as I suppose. I am very much indebted to Mr. Grebnitzki for a skull of each of the species, for one of which I should like to propose the name _Berardius bairdii_, as a slight token of my esteem and gratitude. As I am now almost without any literary means, I find it impossible to decide with certainty in what genus this species will finally have to be placed. But I think that the supposition that this specimen (No. 1520) is a young _Berardius_ may not be far out of the way. At first I suspected that it is a _Dioplodon_, but the size of the skull, in connection with the distinctness of the sutures, the evident maxillary crests, and the terminal position of the teeth very soon led me to the above conclusion.