One of XXII 4 a the most characteristic anatomical distinctions between the porpoise and other members of the Delphinidae is the form of the teeth (numbering twenty-three to twenty-six on each side of each jaw), which have expanded, flattened, spade-like crowns, with more or less marked vertical grooves, giving a tendency to a bibbed or often trilobed form (fig.   anvd [Please select]

In several genera, namely, Pæcilasma, Dichelaspis, Conchoderma, and Alepas, the scuta show a tendency to be bilobed or trilobed.   anvd [Please select]