Art. 21 TEXAN PLEISTOCENE VERTEBRATES HAY 11 



The lower right second molar (pi. 5, fig. 3) is so deeply worn that 

 all of the dentinal areas are confluent and nearly all traces of trefoils 

 are obliterated. The length was originally close to 125 mm. The 

 width in front is 75 mm. ; at the rear, 90 mm. There were three 

 crests; also a talon, which was nearly destroyed by the pressure of 

 the succeeding tooth and by the wear of mastication. The valleys 

 are shown to have been wide to their bottoms. A large, well-worn 

 tubercle is seen at the outer end of each A^alley and one at the inner 

 end of the second valley. The tooth was apparently somewhat 

 twisted outward during burial. 



The lower right third molar presents a crown complete, except 

 where worn by usage during life (pi. 2, fig. 1; pi. 5, fig. 3). The 

 roots are mostly missing. The length of the crown is 223 mm. ; the 

 width at the first crest, 88 mm. ; at the second, 92 mm. ; at the third, 

 95 mm. ; at the fourth, 92 mm. ; at the fifth, 72 mm. All the crests 

 are worn, the hindmost only slightly ; none so much as to allow the 

 dentine areas of the opposite ends of the crests to coalesce. The orig- 

 inal heights of the crests can not, on account of the wear, be exactly 

 determined. In the condition of wear, and measured on the slope 

 from the lower border of enamel to the worn summit, the heights of 

 the inner cones, from the first to the fifth, are as follows in milli- 

 meters: 51, 47, 58, 61, 55. The probable original elevations were 

 greater by from 13 mm. in the second to 5 mm. in the fifth. The 

 heights of the outer cones similarly measured are, in millimeters, 34, 

 39, 45, 53, 57. Trefoils are found on the outer halves of all the 

 crests, although the lobes descending from the pretrite half of the 

 fifth crest into the fourth valley are absent. The enamel of the 

 trefoils and of the inner ellipses is little folded. There are no 

 traces of trefoil-producing buttresses on the inner halves of the 

 crests. Besides a fifth crest, there is a well-defined talon. A small 

 amount of cement appears in many of the valleys, especially in the 

 one between the last crest and the talon. A large patch of it is 

 present at the outer end of the fourth valley. 



The fifth crest requires further description. On the pretrite side 

 it presents two cones, a large outer one and a small, thinner one next 

 to the median cleft. No buttress appears on the front face of this 

 half of the crest. On the rear face of the principal cone is a ridge, 

 which may represent a buttress. On the posttrite side are two cones. 

 The one on the lingual side resembles its homologue in the other 

 crests. The other, the one next to the median cleft, is greatly 

 enlarged, being 21 mm. wide in the right tooth, 24 mm. in the left. 

 It is expanded forward, especially in the tooth of the left side, so 

 as to join the pretrite buttress of the crest in front, partially block- 

 ing the fourth vallev. In the tooth of the left side this cone sends 



