EXTINCT MAMMALIA OF NORTH AMERICA. 



423 



A tooth retained in the left maxilla is now lost, but is represented in three views, 

 together with three views of the skull in an unpublished plate by Professor Agassiz. 

 The tooth, a double-fanged molar, is intermediate in size and character with the cor- 

 responding ones of Squalodon atlanticus and S. pelagius. The crown is compressed 

 conical, longer than broad, and has both its acute borders serrated. The enamel pre- 

 sents a row of rugosities near the base externally, but appears generally to have been 

 nearly smooth. According to Mr. Tuomey, the length of the crown v^as seven-eighths 

 of an inch ; the breadth five-eighths of an inch. 



In its present condition the skull measures about fifteen inches, but when perfect 

 has approximated two feet in length. Other measurements derived from the specimen 

 are as follow : 



Height from inferior margin of occipital foramen to summit of inion, 

 Breadth of inion at paramastoids, ... .... 



Breadth of occijiital foramen, . . . . . 1 in. 4 1. 



Vertical diameter of condyles, . . . . 1 in. 7 1. 



Width fore and aft of temporal fossa, 



Height of do. obliquely from zygoma, ...... 



Breadth of vertex at boundaries of temporal fossre, 



Breadth of cranium just below A'ertex, ...... 



Distance from summit of inion to frouto-parietal suture, . 



Breadth of skull at mastoids, ........ 



Breadth of skull at f)ost-orbitals, ....... 



Height of do.. 

 Transverse do.. 



5 in. 2 1. 



7 in. 



1 in. 1 1. 

 1 in. 



4 in. 7 1. 



3 in. 7 1. 



1 in. 6 1. 



2 in. 1 1. 

 1 in. 1 1. 



8 in. 4 1. 



Squalodon protervus. 



Cynorca 2}>-oterva, Cope: Proc. Acad. Nat. Sc. 1867, 144, 151; 1868, 185. 

 Squalodon protervus, in part of Cope : Proc. Acad. Nat. Sc. 1867, 151. 

 Cynorca, In part of Cope : Ibidem, 152. 



Four isolated teeth, from Ashley River, South Carolina, apparently indicate a small 

 species of Squalodon, which may perhaps be the same as that described under the 

 name of S. pelagius. Two of the teeth represented in figures 18, 19, plate XXVIII, 

 together with the canine tooth of a Peccary, are the specimens upon which Prof. 

 Cope founded the distinctive characters of his Cynorca proterva or Squalodon proter- 

 vus. He was unaware, he informs nie, that I had already described and had had 

 figured the former teeth in preparation for the present synopsis. 



One of the teeth, a molar, represented in figure 19, approaches in form and size 

 that of the jaw fragment referred to S. pelagius. The crown is, however, longer, nar- 

 rower and thinner; the length being greater than the breadth. It is also less straight 

 or more curved inwardly and is comparatively smooth externallj', and less rugose 

 internally. Its surfaces also are more evenly convex or not impressed approaching 

 the acute borders. The fangs, partially connate, indicate a more anterior position 



