480 FIELD COLUMBIAN MUSEUM ZOOLOGY, VOL. III. 



Color. Black. 



Measurements. Total length, 20 feet. 



13. Ziphius. Cuv., 1823. 



PAGE. 



24. Ziphius cavirostris. Cuv 17 



25. *grebnitzkii. (Ziphius), Stejneger, Proc. U. S. Nat. Mus., 1883, 



P- 77- 



Type locality. Bering Island. 



Genl. Char. "The tip of the beak is obtuse, with a vertical 

 furrow in the middle, the lower jaw with the two terminal teeth pro- 

 truding considerably beyond the upper one. From about the middle 

 of the beak towards the tip, the mesethmoidal, ossified in its whole 

 length, arises, like a rounded staff, between and above the premax- 

 illaries, following these to the tip and being totally fused together 

 with them. The nasal groove is very unsymmetrical, owing to a 

 very prominent asymmetry of the premaxillaries and the nasals, so 

 that the direction of the oblique nares forms an angle of not less than 

 20 degrees with the vertical plane through the longitudinal axis of the 

 skull. The right os nasale and the premaxilla of the same side are 

 by far the larger ones, and form the principal part of the roof above 

 the nares, the nasal not reaching, however, so far forward as the pre- 

 maxilla. The ante-nasal groove is large, and in the anterior half 

 partly vaulted over by the edges of the premaxillaries, which are 

 somewhat bent inwards. The zygomatic process of the squamosals 

 touches the orbital of the frontals without coalescing however. The 

 jugale is not narrower in the fore part, which, consequently, is not 

 dilated and does not reach the posterior maxillary notch. This is 

 not particularly deep, and the anterior one is still more shallow. The 

 visible part of the vomer is long and narrow, commencing 124 mm. 

 from the tip of the beak. The supraoccipital is rather inclined for- 

 wards, forming an angle of about 40 degrees, with a line parallel to 

 the vertical axis of the skull." 



Measurements. " Length of the skull in straight line, 983; great- 

 est breadth, 600; length of beak from anterior maxillary notch to tip, 

 485; length of right nasal, 135; of left nasal, 128; length of lower 

 jaw, 845; length of symphysis, 180; longitudinal diameter of tooth 

 at base, 26; height of tooth, 36." (Stejneger, 1. c.) 



14. Mesoplodoii. Gerv., 1850. 



26. Mesoplodon bidens. (Sowerby.) 18 



* Omitted in the Synopsis. 



