7. _Berardius bairdii._ Centerville, California.

Ventral aspect. Nat. size.

[Illustration: Plate 35 TYMPANIC BONES OF MESOPLODON, ZIPHIUS, AND

BERARDIUS]

Tympanic bones of _Mesoplodon_, _Ziphius_, and _Berardius_.

Fig. 1. _Mesoplodon densirostris_ (?). Annisquam, Massachusetts.