_Berardius._[148]—Two moderate-sized, compressed, pointed teeth on each side of the symphysis of the mandible, with their apices directed forwards, the anterior being the larger of the two and close to the apex. Upper ends of the premaxillæ nearly symmetrical, moderately elevated, very slightly expanded, and not curved forward over the nares. Nasals broad, massive, and rounded, of nearly equal size, forming the vertex of the skull, flattened in front, most prominent in the middle line. Anteorbital notch distinct. Rostrum long and narrow. Mesethmoid only partially ossified. Small rugous eminences on the outer edge of the upper surface of the maxillæ at base of rostrum. Vertebræ: C 7, D 10, L 12, C 19; total 48. The three anterior cervicals ankylosed, the rest free and well developed. The only known species, _B. arnuxi_, attains the length of 30 feet, and has hitherto only been met with in the seas around New Zealand. _Choneziphius._[149]—The rostral portions of crania from the Antwerp and Suffolk Crags, on the evidence of which this genus has been established, agree with those of _Mesoplodon_ in having the premaxillæ in contact with the intervening bones throughout the length of their inner surfaces, and also in showing only a very small portion of the vomer on the inferior surface; they differ, however, in that the mesethmoid cartilage remains unossified, whereby a fistular vacuity remains. In some species the soldering of the inner surfaces of the premaxillæ is incomplete. The interorbital region of the skull is flat; and there are two pits in the nasal region, of which the right is the larger. _Family_ SQUALODONTIDÆ. Numerous extinct forms, chiefly known by teeth and fragments of crania, may be provisionally placed here, until more of their osteological characters shall be brought to light. They differ from all existing Cetaceans in having the teeth distinctly differentiated into groups, as in the Archæoceti, the posterior molars being two-rooted. The cranium has, however, none of the distinguishing characteristics of the Zeuglodonts, but essentially resembles that of the Odontoceti, especially in the position of the anterior nares and form of the nasal bones.