42 Guide to Whales, Porpoises, and Dolphins. 
Continent, the skull has a long and slender beak, but in the South 
American Prosqualodon it is much shorter. In the last-named 
genus the nasal bones, instead of being reduced to mere nodules, 
as in the Delphinidx, roof over the hind part of the cavity of the 
nose. The Squalodontide are a more primitive type than the 
Delphinide. 
The dental formula of the type genus Squalodon is now given 
as 1.3,C.4,Pm.%;°, M.325. Several species of this genus, such 
oes =o 
as Squalodon grateloupi (fig. 31) are represented by plaster-casts 
of the skull, while of Prosqualodon an imperfect skull from the 
Miocene formation of Patagonia is shown. ‘'T'wo small species, 
Microsqualodon gastaldii and Neosqualodon assenze, have been 
made the types of distinct genera. 
Hire, Bil 
Imperfect Skull of a Shark-toothed Dolphin (Squalodon grateloupi). 
About 4 natural size. 
An imperfectly known Cetacean skull with serrated teeth, from 
a Tertiary formation in South Carolina, has been named Agorophius. 
This skull differs from those of Squalodon and modern Cetaceans 
in that the parietal bones occupy a long area on the roof of the 
skull, instead of being almost entirely excluded by the approxima- 
tion of the frontal and supraoccipital bones at the vertex. This 
conformation suggests that the Shark-toothed Dolphins originated 
from a group unlike the under-mentioned Zeuglodonts. 
ce In the Eocene deposits of North America, Europe, 
Primitive tie 
and Northern Africa occur remains of Whale-like 
Whales. 
creatures—mostly of large size—known as Zeuglo- 
donts, and constituting the suborder Archoceti and the family 
