TRANSACTIONS OF WAGNER 



22 



MASTODON 



with stronger medial offsets directed to the inner lobes, display but little dis- 

 position comparatively to form tubercular offsets in front and behind. 



Of several other specimens of teeth associated with those just described, 

 I feel more uncertain as to their exact relative position. 



Plate iv. fig. 3 represents the crown of what I suspect to be an upper 

 second milk molar of the right side. It appears to have been composed of 

 two pairs of lobes and an additional third inner lobe. It is partially worn so 

 as to display exposed dentinal areas on the paired lobes, and is imperfect at 

 the fore inner part. It is fore and aft quadrate oval, and appears to have been 

 inserted by a pair of fangs. 



In comparison with the other teeth above described, this one is somewhat 

 peculiar in the proportionately more distinctly tubercular condition of the 

 crown and in the strongly longitudinal wrinkled state of the constituent lobes. 

 The lateral surfaces of the lobes are prominently convex and comparatively 

 even, but those in front and behind are ridged longitudinally. 



The first inner lobe is continuous with the remains of a stout process, 

 similar to that in the back molar teeth, extending in advance of the contiguous 

 inner lobe, and at its back part with another stout process, which appears as a 

 development of the basal ridge at the outer part of the crown, extending to 

 the third inner lobe. Its summit is worn away so as to display a broad 

 dentinal area, which appears to have extended on both processes just indicated. 

 The second inner lobe, also considerably worn away at the summit, is devoid 

 of a posterior buttress, except as a tubercle at the bottom of the correspond- 

 ing valley. The third inner lobe, more prominent than the former, is unworn, 

 conical, with a nipple-like summit, and is provided with three conspicuous 

 offsets, as anterior, medial, and posterior buttresses. The outer lobes, partially 

 divided, each into a pair of sublobes, are strongly marked in front and behind 

 with buttress-like ridges or tubercular offsets. The summit of the first outer 

 lobe is worn so as to display a considerable reniform dentinal area, that of the 

 second displays a pair of small dentinal islets. Back of the second outer lobe 

 the crown is occupied by a group of conspicuous tubercles, springing from the 

 basal ridge and apparently representing a third outer lobe. A conspicuous 

 process of the basal ridge also occupies the interval externally between the 

 outer lobes of the crown, to the fore part of which descends a strong ridge 

 from the first outer lobe. The transverse diameter of the tooth behind is 40 

 mm., the height of the crown at the third inner lobe 27 mm. 



The imperfect second left lower milk molar, shown in plate iv. fig. 4, 



