2. Skull. Barnegat City, New Jersey. Lateral aspect. ⅙ nat. size.

3. Skull. (Type of _Ziphius grebnitzkii_ Stejneger.) Bering Island. Cat.

No. 20993, U.S.N.M. Lateral aspect. ⅙ nat. size.

[Illustration: Plate 21 SKULLS OF ZIPHIUS CAVIROSTRIS]

_Ziphius cavirostris._

Fig. 1. Skull. Newport, Rhode Island. Lateral aspect. 1/7 nat. size.

2. Skull. (Type of _Ziphius semijunctus_ (Cope).) Charleston, South

Carolina. Posterior aspect. 1/7 nat. size.