610 The American Naturalist. [July, 
But few species of this family are known from terranes of earlier 
than Pliocene age, and they belong to existing genera. Extinct 
species of Delphinapterus and Orca have been found in the 
Italian Pliocene, and of Orca and Globiocephalus in England. 
In North America the Delphinapterus orcinus has been des- 
cribed from the Miocene of North Carolina, and the D. vermont- 
3 
; FIG. 6.—Prodelphinus crotaphiscus C. pe (fi 
tion of muzzle. About one-fifth natural size. 
anus has left its remains in the so-called Champlain clays of the 
drainage basin of the St. Lawrence river, which are perhaps of 
Plistocene age (Plate XXI). 
MYSTICETE. 
This suborder embraces but a single family, the Balenide, 
whose characters may be summarized as follows : 
Nareal canal oblique, overroofed by the short horizontal 
nasal bones, and underroofed by the elongate ptery- 
type); 1, above, 2, from side; 3, sec- 
