_21245. Bering Island._—Nearly all sutures between maxillæ and premaxillæ at end of rostrum, above and below, anchylosed together, but majority of others traceable. Condition of superior surface of skull very similar to that of preceding, but premaxillæ rather low at distal end. Mesirostral at distal end rather lower than premaxillæ and concave superiorly; more posteriorly assuming form of a narrow ridge, with a deep channel between it and premaxillæ on each side. More posteriorly still it widens rapidly, with a convex surface, and terminates abruptly with a truncated end, the surface of which is concave. A deep basin around nares, as in preceding skull. Orifice of anterior nares far below level of nasal boss. The latter largely absorbed and deeply undercut and concave in front. Nasal septum terminating before reaching lower end of nasals, and ridge on latter low and traversing left nasal. Sides of premaxillæ at distal end very concave. Rudimentary alveolar groove nearly obsolete. Rostrum blunt at apex, and about as deep as wide at anterior ends of maxillæ. (Pl. 16, fig. 2.) _21248. Bering Island._—Similar to preceding, but mesirostral ossification higher than premaxillæ at distal end and convex above; less abruptly widened posteriorly and posterior termination flat. Narrow, deep grooves between ossification and premaxillæ on each side, or, in other words, premaxillæ more closely approximated to sides of mesirostral distally. Basin around nares and conformation of the several bones bordering it similar to preceding. Sides of premaxillæ concave at distal end, the grooves thus formed in them intruding some what on the maxillæ, especially posteriorly. Apex of rostrum very blunt, rounded off below and projecting above; deeper than wide. Rudimentary alveolar groove nearly obsolete. (Pl. 17, fig. 1; pl. 22, fig. 4.) Rami of mandible anchylosed together and the symphysis and suture largely obliterated. Teeth very broadly fusiform; tip short and rather blunt; roots closed; diameter 30 mm.