84 BULLETIN 73, UNITED STATES NATIONAL MUSEUM. 



Plate 7. 



Fio. 1. Mesoplodon bidens. Skull. Nantucket, Massachasetts. Female, adult. Mus. Comp. Zool. 

 No. 1727. Lateral aspect, i nat. size. 

 Tip of beak, left pterygoid and malar defective. 

 2. Mesoplodon densirostrisf Skull. Annisquam, Massachusetts. Female, young. Boston Soc. Nat. 

 Hist. Lateral aspect. J nat. size. 

 Distal portion of beak defective and warped. 



Plate 8. 



Fig. 1. Mesoplodon curopa-us. Skull. Atlantic City, New Jereey. Male, young. Cat. No. 23346, 

 U.S.N.M. Lateral aspect. About i nat. size. 

 2. Mesoplodon euro pxus. Skull. North Long Branch, New Jersey. Female, adult. Mus. Comp. 

 Zool. Lateral aspect. About J nat. size. 

 Distal portion of beak lacking. 



Plate 9. 



Fig. 1. Mesoplodon stejnegeri. Type-skull. Bering Island. Immature. Cat. No. 21112, U.S.N.M. 

 Lateral aspect. About -} nat. size. 

 Premaxilla-, maxilUe, frontals, zygomatic process, etc., defective. On account of these defects 

 and the immaturity of the individual the forward inclination of the supraoccipital is much 

 greater than in the skull shown in fig. 2. 

 2. Mesoplodon slejnegeri. Skull. Yaquina Bay, Oregon. Adult. Cat. No. 143132, U.S.N.M. 

 Lateral aspect. \ nat. size. 

 Proximal end of premaxilla' defective. 



Plate 10. 



Skvills of Mesoplodon. 



Fig. 1. Mesoplodon hidens. Nantucket, Massachusetts. 



2. Mesoplodon densirostris'! Annisquam, Massachusetts. 



3. Mesoplodon eiiropn'us. Atlantic City, New Jersey. 



4. Mesoplodon eiiropxus, North Long Branch, New Jersey. 



5. Mesoplodon stejnegeri. Type-skull. Bering Island. 



6. Mesoplodon stejnegeri. Yaquina Bay, Oregon. 

 Posterior aspect. All figures \ nat. size. 



Plate 11. 



Mandibles of Mesoplodon. 



Figs. 1, 2, and 5. Mesoplodon bidens. Nantucket, Massachusetts. 

 3 and 6. Mesoplodon europieits. Atlantic City, New Jersey. 

 4. Mesoplodon stejnegeri. Yaquina Bay, Oregon. 

 All figures \ nat. size. 



Plate 12. 



Fig. 1. Mesoplodon stejnegeri . Yaquina Bay, Oregon. Mandible and tooth. J nat. size. 



2. The same. Left mandibular tooth. Outer surface. 



3. The same. Right mandibular tooth. Inner surface. 

 All figures a little more than ^ nat. size. 



