44 Guide to Whales, Porpoises, and Dolphins. 
The typical genus Zeuglodon is connected by means of certain 
genera like Prozeuglodon (fig. 33) and Protocetus from the Eocene 
formations of Egypt so closely with the primitive Hocene Carnivora 
known as Creodontia that there can be no hesitation in admitting 
the descent of the Zeuglodonts from carnivorous land-animals. 
The relations of Zeuglodonts to the Shark-toothed Dolphins and 
modern Toothed Whales are not, however, at present fully under- 
stood, although, as mentioned above, it is doubtful if any of the 
known genera of Primitive Whales can be regarded as directly 
ancestral to the Shark-toothed Dolphins. 
Ie BBY 
Lateral and top views of the Skull of a Primitive Whale (Prozeuglodon atroz). 
About 4, natural size. 
pmex., premaxilla ; nar., nares ; 2a., maxilla; aof., anterior orbital foramen: /7., frontal ; 
la., lachrymal ; p.orb., post-orbital process ; opt., optic fissure; ju., jugal; a/., alisphencid , 
pa., parietal; soc., supra-occipital ; sq., squamosal; zyg., zygoma; cond., condyle ; 
pgl., post-glenoid process: na., nasal. (After GC. W. Andrews.) 
