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laterally*, and has very distinct anterior and posterior cusps, the 

 former being much the more prominent. There is an almost semi- 

 circular valley between the two, from which a wearing surface 

 slopes upwards on the inner and hinder face. In the closed jaw 

 this comes in contact with the outer surface of the first molar of 

 the mandibular set. 



Four molars follow, and one description will suffice for the 

 three anterior, which resemble one another almost exactly in size 

 and shape ; the hindermost is smaller and less complex. 



Taking the first member of the series, which is that shown in 

 PI. YI., figs. 3 — 6, it is compressed antero-posteriorly and 

 mostly so in its mid region, so that the length of the long axis 

 of the crown, which is about twice that of the greatest width, 

 lies exactly athwart the alveolar border. As seen externally 

 (fig. 4), the prominent feature is a pointed, inverted triangular 

 cusp (a), of which the apex corresponds to the centre of the 

 crown when viewed in plan. From the apex of this cusp a 

 concavo-convex surface, showing signs of wear, trends upwards 

 and outwards to the angles at the base, where there are 

 two small but distinct anterior and posterior external cusps 

 (h and c). Between these cusps is a groove, which extends ver- 

 tically to the alveolar edge. The internal face of this prominent 

 apical cusp passes vertically upwards as a smooth rounded border 

 to nearly the level of the palate, then spreads out internally into 

 a concave, subtriangular, overhanging surface also showing signs 

 of wear (figs. 5 and 6, d). The concavity of this overhanging 

 surface being due to the fact that it is bordered by a well-marked 

 rim, which descends internally into an internal cusp (e) ; from 

 the apex of this, the internal contour passes upwards to the level 

 of the palate (fig. 5, j^) as a smooth border rounded from below 

 upwards, and still more sharply so, from before backwards. 

 The whole of this part of the tooth has somewhat the shape of 

 the upper bill of a parrot, if it were much blunted and made to 

 have a rounded end instead of a sharp point, or a better simile, 

 perhaps, would be the peak of a military helmet. The horizontal 

 level of this beak-shaped internal cusp is about that of the edge 

 of the alveolar border, though, from the transversely archlike 

 trending of the palate away from this border it stands as much 

 below this surface as it is above the median pointed cusp. 



* From the fact that this tooth is placed just where the narrow part of 

 the pyriform area, marked out by the alveolar border, suddenly broadens 

 into the wider end, the outer face of this tooth looks forward as well as 

 outwards. Instead, therefore, of speaking of it as laterally compressed, it 

 would be more correct to say that the axis of compression runs from a 

 point outside and in front to within and behind ; or, in other words, the 

 long axis of the crown if continued forwards would strike the canine of the 

 opposite side. ( Vide PI. VII. , fig. 2. ) 



