238 VERTEBRATE REMAINS, PORT KENNEDY BONE DEPOSIT. 



a larger lobe or entoconid and a smaller between it and the lobe representing the 

 metaconid. Entoconid not elevated, resembling that of the extinct species of 

 Mephitis already described. No cingula. The tubercular molar has a semi-circular 

 concave grinding surface, and no cingulum. 



Measurements. 



mm. 



Length of ramus from canine to condyle, inclusive ; 42 

 Depth of ramus at pm T ; 7 



" " at m-2 ; 8 



Depth at condyle; 7.5 



" at coronoid process ; 22 



Length of dental series ; 25 



" of true molars; 12 



Diameter of base of crown of canine ; 3.5 



Elevation of crown of canine; 4 



f elevation; 3.5 



Diameters of crown of sectorials anteroposterior; 8.5 



( width of heel ; 3.5 



The jaw described is about the size of that of the common skunk. 



LUTRA Linn. 

 Lutra rhoadsii Cope (PI. XVIII, figs. 11, 11a). Proc. Acad. Nat. Sci. Phil., 1896, p. 391. [Type No. 61, 

 Mus. Acad. Nat. Sci. Phil.] 



Portions of both mandibular rami with the right superior tubercular molar 

 represent this otter. The right ramus supports part of one of the premolars, a 

 large part of the sectorial and the tubercular. The left ramus supports the tuber- 

 cular. In the right ramus the alveoli of the premolars and part of that of the 

 canine are preserved. All belong to one individual, and were found in place in the 

 matrix. 



This species differs from Lutra canadensis in two conspicuous points : first, the 

 inferior border of the mandible is a nearly straight line to the angle ; second, the 

 third premolar is nearly transverse to the long axis of the jaw in position in conse- 

 quence of the much shorter mandibular symphysis. 



The coronoid process is at right angles to the horizontal ramus, and its anterior 

 and posterior borders are straight and of equal inclination to the obtuse apex ; the 

 posterior border is convex in L. canadensis. The condyle is opposite the base of 

 the sectorial ; in L. canadensis it is opposite the apices of the cusps of the sectorial. 

 The anterior border of the masseteric fossa is below the middle of the tubercular 

 molar. The inner side of the ramus is flat and not grooved, except immediately 

 above the angle. The mental foramina are below the middle of the first and the 

 anterior root of the second premolars. • 



Both the internal and external border of the inferior tubercular molar are 

 elevated. The former as a low cusp. The crown is horizontal in position and is not 

 tipped forward as in L. canadensis. An external basal cingulum on both this tooth 



