66 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



PLATE 6 



Lateral aspect of skulls of toothed cetaceans, figs, i, 2, and baleen whales, 

 figs. 3, 4. 



Fig. I. Physeter, very young. No. 49488, U. S. Nat. Mus. 



Fig. 2. Platanista. No. 172409, U. S. Nat. Mus. (The lacrimal and very 

 short jugal are almost concealed beneath the overhanging edge of the 

 orbit. The posterior orifice of the antorbital canal is visible above 

 the edge of the zygomatic process of the squamosal in the region 

 where the process comes in contact with the orbital portion of the 

 frontal ; above the orifice of the antorbital canal is a slit-like vacuity 

 in the wall of the optic canal.) 



Fig. 3. Balcenoptera. No. 236680, U. S. Nat. Mus. 



Fig. 4. Eubalcena. No. 23077, U. S. Nat. Mus. 



