_21975. Charleston, South Carolina._—Young female. (Type of _Z. semijunctus_.) All sutures open, and elements of occipital bone distinguishable. No mesethmoid ossification. Opposite maxillary notches, premaxillæ closely approximated, nearly flat and horizontal, and about level with adjacent parts of maxillæ. Left premaxilla grooved longitudinally at this point. Orifice of anterior nares on a level with lower end of rectangular projecting boss formed by superior portion of nasals. Rostrum pointed, much broader distally than it is deep. A very distinct rudimentary alveolar groove in distal end of each maxilla. Proximal end of vomer resting against anterior face of nasals and reaching up to overhanging boss. Anterior face of the latter nearly flat. (Pl. 14, fig. 1; pl. 18, fig. 1; pl. 20, fig. 1; pl. 21, fig. 2.) Rami of mandible not anchylosed together at symphysis. Teeth hollow, open at the root, acute at apex, tipped with enamel; diameter 10 mm. (Pl. 22, fig. 1; pl. 24, fig. 1.) _20971. Barnegat City, New Jersey._—Adult female. Majority of sutures open, but those on superior surface of rostrum between maxillæ and premaxillæ partly anchylosed. Vomer nearly all anchylosed to rostral portion of premaxillæ; it presents a slight median elevation, but there is no mesirostral ossification. Right premaxilla in front of nares broad, flat, and horizontal; left, nearly so, but with a quite broad longitudinal groove. Opposite maxillary notches premaxillæ nearly on a level with adjacent parts. Orifice of anterior nares level with lower end of nasal boss. End of rostrum quite acute, and broader than deep. Rudimentary alveolar groove distinct distally. Proximal end of vomer anchylosed with anterior face of nasals and reaching up to nasal boss, which has a sharp median ridge completing nasal septum superiorly. Anterior face of nasal boss slightly concave on each side of median line. (Pl. 14, fig. 2; pl. 18, fig. 2; pl. 20, fig. 2; pl. 21, fig. 3.) Rami of mandible anchylosed together at symphysis and suture largely obliterated. Teeth slender, cylindrical, rugose, rather blunt; roots closed; diameter 13 mm. (Pl. 24, fig. 3.) _22069. Bering Island._—Adult female? All the sutures about as in preceding specimen. Mesirostral ossification distinct, rounded, extending from base of rostrum nearly to apex, but disappearing before reaching line of anterior ends of maxillæ. Its upper surface below that of premaxillæ. Premaxillæ approximated, and right premaxilla with an angular process near base of rostrum overlapping mesirostral ossification. Premaxillæ at base of rostrum, anterior nares, proximal end of vomer, and nasals as in preceding skull. Apex of rostrum moderately acute, broader than deep. Rudimentary alveolar groove shallow. (Pl. 15, fig. 1.) Rami of mandible anchylosed together and suture largely obliterated. Teeth somewhat fusiform, blunt; roots closed; diameter, 14 mm. (Pl. 22, fig. 3.)