116 INSECTIVOEA. 



side, convex externally and concave internally. The root of the tooth curves back 

 abruptly from the crown. 



The second incisor partakes somewhat of the character of the canine in having 

 its anterior and posterior margins parallel for a certain length, and in the bevelling 

 off of the anterior to the posterior margin. Opposite to where this takes place, 

 there is a faint concavity on the posterior margin of the tooth. It is also laterally 

 compressed and broadest from before backwards. It is directed forwards and 

 downwards, and is shorter than the canine, which has a nearly similar but more 

 vertical course. 



The first incisor is also broadest from before backwards with a similar curve, 

 combiued with a divergence or outward curve of the tooth ; so that when viewed 

 in front, its external margin is concave and its internal margin is convex. The 

 crown and root together of these incisor teeth form a considerable curve. They are 

 directed forwards and backwards. 



The third deciduous premolar in the lower jaw resembles the molars in every 

 respect, only it is considerably smaller than the first. Internally it shows three cusps, 

 of wliich the central one has the greatest vertical length ; and externally it is com- 

 posed of two large triangular cusps, the anterior of which, the most vertically elongated 

 of all, is connected to the two anterior of the internal cusjis by a ridge running to the 

 anterior border of the foremost and to the posterior margin of the hindmost, enclosing 

 a triangular hollow. The cusps posterior to this are on a much lower level and 

 below all the upper cusps. Besides the external and internal cusps, there is another 

 which may be termed posterior, and which is behind and external to the last internal 

 cusp. It is connected to the external cusp by a concave ridge, and it has little 

 or no vertical extension. It corresponds to the middle cusp of the internal series, 

 to wliich it rightly belongs. It is separated from the hindmost internal cusp by 

 a deep notch ; it has only two fangs corresponding to the two triangular surfaces 

 of the crown. 



The second premolar (in lower jaw) is a bi-cuspidate tooth, consisting of one large 

 anterior sub-triangular cusp mth a rather prominent talon at its base posteriorly. 

 The large cusp is concave posteriorly and convex anteriorly, where its upper surface 

 is bevelled off from before backwards, producing a rather prominent angle. The inner 

 surface is convex in the middle line, but grooved on either side of it. It has two 

 divergent fangs which partially embrace the crown of the permanent tooth, but are 

 so external to it that it cannot be detected when the roots of the teeth are laid bare 

 from without. Tliis tooth differs little from the permanent tooth, which is larger. 



The first premolar (lower jaw) is laterally compressed, convex anteriorly and 

 concave posteriorly, in profile, the latter margin running nearly to the tip or point of 

 the crown of the tooth, from which it is separated by a short bevelled surface : the 

 point rounds off to the anterior margin. At the posterior margin, the angle formed 

 by the crown of the tooth and the siugle cyhndrical tapering fang, corresponds to 

 the posterior talon of the second premolar. Its permanent tooth hes immediately 

 below its root. 



