62 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. "](> 



PLATE 4 



Comparison between the lateral aspect of the maxillary of a zeuglodont, 

 fig. I, a toothed cetacean, fig. 2, and a baleen whale, fig. 3. The large orbital 

 plate in the baleen whale is a structure which is absent in both the zeuglodont 

 and the toothed cetacean. 



Fig. I. Prozeuglodon (from C. W. Andrews). 

 Fig. 2. Grampus. No. 15773, U. S. Nat. Mus. 

 Fig. 3. Balenoptera. No. 20931, U. S. Nat. Mus. (The missing lacrimal lay 



in the depression of the maxillary in front of the jugal, as may be 



seen in fig. 3 of plate 6.) 



