208 CHIEOPTBRA 



forming true basal cusps. Mandibular canine low and heavy, 

 its apex scarcely rising above level of highest molar cusps, its 

 greatest diameter measured along cingulum nearly or quite equal 

 to length of anterior border of shaft ; cingulum well developed, 

 forming a distinct antero-basal cusp, the apex of which rises to 

 level of middle of posterior border of shaft. Anterior upper 

 premolar with area of crown approximately equal to that of upper 

 incisor and about one-fifth that of canine. It is somewhat 

 crowded inward from tooth-row, though about half of its crown is 

 visible from outer side in space between canine and large 

 premolar ; main cusp short but well developed, lying somewhat 

 in front of middle of crown, the general form of the tooth much 

 like that of canine but proportionally lower. Large upper 



premolar with crown area about equal to that 



) of canine or slightly greater, the inner portion 



/?V^ ^ narrow and flattened-concave, with evident 



-^?T\l elevated rim, the posterior border strongly 



Cx 3 . „ f\ concave, the anterior border usually convex 



30 but occasionally a little concave ; height of 



main cusp slightly greater than that of highest 

 fig. 35. molar cusps and about equal to length of 



*K£Mh x ""*■ tooth along outer cingulum, posterior cutting 



edge well developed ; secondary cusp low but 

 evident, rising from cingulum at antero-internal base of main 

 cusp. Lower premolars with crown areas not conspicuously 

 unequal, though that of second perceptibly greater than that of 

 first ; outline of crown of each tooth rhombic, the outer border 

 somewhat convex, the anterior border of second relatively shorter 

 than that of first ; cingulum well developed, forming a slight 

 antero-internal basal cusp ; main cusp triangular in outline when 

 viewed from the side, that of second as high as molar cusps, that 

 of first shorter, the antero-external surface of each tooth convex, 

 the internal and posterior surfaces concave. First and second 

 upper molars sub-equal, though transverse diameter is relatively 

 greater in latter than in former ; inner border rather narrowly 

 rounded, the region of greatest convexity a little in front of 

 middle ; anterior and posterior borders straight or slightly 

 concave ; protocone robust though rather low ; hypocone small 

 but well developed, though not completely distinct from posterior 

 commissure of protocone ; metacone higher than paracone ; styles 

 well developed ; VV-p a ttern normal ; m 3 with crown area about 

 two-thirds that of m 1 , the hypocone absent, the metacone smaller 

 than paracone ; no trace of metastyle or fourth commissure. 

 Lower molars with no special peculiarities ; protoconid higher 

 than hypoconid in all three teeth ; hypoconid with greater basal 

 area than protoconid in m. 1 and m 2 , but with less in m 3 ; cingulum 

 well developed, forming a slight postero-internal cusp behind 

 entoconid. 



Measurements. — Adult male from Henley-on-Thames, Oxford- 



