58G PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



The specimen is very young. In the skull the basi-sphenoidal suture 

 is open and the outlines of the elements of the occipital bone are still 

 faintly marked. All the bones are very brittle and many are badly 

 broken. Phalanges and pelvic and hyoid bones are wanting. 



I find no flaw in the brief original description by Professor Cope. 

 Of the 10 pair of ribs, however, that belonging to the right side has 

 been lost. The total number of vertebrse is 47, but the last three are 

 restorations in wood. About that number are needed, however, to prop- 

 erly complete the backbone. 



The specimen is unquestionably a Ziphius, and the opinions of Pro- 

 fessors Flower and Van Beneden in regard to it are, therefore, sustained. 

 Whether it is distinct from Z. cavirostrift or not I am unable to de- 

 termine. My observation leads me to believe that in this genus the 

 changes in the conformation of the skull in front of the anterior nares, 

 as a consequence of age, rival those affecting the maxillary crests in 

 Hypcroodoii. There appears to be a progressive excavation or absorb- 

 tion of the bones lying in the median line of the upper surface of the 

 beak, accompanied by iutrovertion of the premaxilhie and a rounding off 

 of the extremity of the beak. Until it has been determined how far 

 these changes are due to age it would seem impossible. to decide upon 

 the real number of existing species. It is perhaps desirable that the 

 Charleston specimen should for the present be known as ZipMus semi- 

 junctus. 



In general form and proportion the skull approaches most closely 

 the Z. Gervaisii of Duvernoy (fig. in Van Beneden and Gervais, Osteog. 

 Cetaces, pi. 21, figs. 1-6). It is least like the Z. indicus of Van Beneden. 

 Its proportions are as follows : 



Measurements of the skull of Ziphius semijunctus (Cope). 

 [No. 21,975.— Type— .] 



Measurements. 



Total length 



Length of beak 



Breadth of beak at base of notches 



Breadth of beak at its middle 



Height of beak at its middle 



Breadth of prcniaxillfe at same point 



Greatest breadth between outer margins 



of premaxilla3 prosimally 



Length of tooth-line 



Last tooth to base of maxillary notch 



Tip of beak to anterior margin superior 



nasal opening 



Tip of beak to end of crest of pterygoid 



in median line 



Breadth between orbital processes of 



frontal . 



MilU- 

 meters. 



797 

 466 

 252 

 82 

 54 

 40 



620 

 395 



Measurements. 



Breadth between hinder margins of tem- 

 poral f ossoe 



Length of temporal fossa 



Depth of temijoral fossa 



Total length of mandible 



Length of symphysis of mandible 



Length of tooth-row of mandible 



Depth between angle and coronoid pro- 

 cess 



Total length of mandibular tooth 



Greatest diameter of mandibular tooth.. 



Vertex to lower margin occipital con- 

 dyles 



Horizontal length of nasals 



Greatest width of both nasals 



Milli- 

 meters. 



244 



124 



72 



678 



134 

 46 

 11 



280 

 95 

 57 



Washington, September 25, 1885. 



