BEAKED WHALES, FAMILY ZIPHIID^ — TRUE. 



29 



The inferior end of the tooth is cut off obliqueh^ and the margin is broken by numer- 

 ous prominent rugosities. The surface of all that part of the tooth which is con- 

 tained in the alveohis and covered by the gum above it is rugose, while the part 

 above the gum is quite smooth and highly polished. 



The right tooth has the following dimensions (in straight Unes): Length of 

 anterior border, 150 mm.; length of posterior border, 107; length of superior border, 

 54; lengthof inferior border, 86; average length of exposed dentine tip, 10; greatest 

 breadth of tooth, antero-posteriorly, 81 ; greatest breadth of tooth, transversely, 

 15; distance from center of base of exposed portion, when in position in the 

 alveolus, to tip of dentine projection, 82; distance from center of base of portion 

 above the gum to tip of dentine projection, 70; distance from center of base 

 of portion above the gum to center of inferior margin, 76. 



The dimensions of the skulls are as follows, those of the type-specimen having 

 been revised a,nd corrected: 



Dimensions of tiro skulls of M. stejnegeri. 



Measurements. 



Totallength 



Length of rostrum 



Distance from occipital condyles to distal end of maxillae. . 



Breadth between centers of orbits 



Breadth between zygomatic processes 



Breadth between temporal foss:e 



Breadth between postorbital processes of Irontals 



Breadth of rostrum at base (between maxillary notches) - 



Breadth of rostrum at middle 



Depth of rostrum at middle 



Greatest breadth of anterior nares 



Greatest breadth of premaxillae proximally 



Greatest breadth of premaxillEe in front of nares , 



Length of temporal fossa 



Depth of temporal fossa 



Antero-posterior length of orbit 



Breadth of foramen magnum 



Length of tympanic bulla 



Breadth of tympanic bulla 



Length of mandible 



Length of symphysis 



Distance from anterior end of mandible to alveolus 



o Tip of rostrum lacking. 



6 The skull is much worn around the left notch and the measurement is only approximate. 



EXTERNAL FORM. 



The photograph of the head (PI. 40, fig. 4) shows that the end of the beak was 

 quite blunt, and the lower jaw quite a little longer than the upper. The superior 

 margin of the lower jaw, which is concave in front of the tooth, is strongly convex 

 and elevated at the side of it and behind it. The inferior margin of the upper jaw 



