272 HIPPOrOTAMUS TEETH OR TUSKS. 



matous, or thick-skinned animals ; and even of this distinct genus, there ia 

 but one living species — " Hippo])otamus amphibius " — found exclusively in 

 certain parts of the African continent.* 



The interest attaching to this animal from an economic point of view, 

 is rather limited, being confined to a local use of its skin and flesh by the 

 African natives and colonists, and the more general application of its 

 powerful teeth, or tusks, as a substitute for true ivory. 



However interesting it might be to consider the general anatomical, and 

 physiological, features of this gigantic creature ; or to trace out the resem- 

 blance thought to exist between it and the " Behemoth," described in the 

 Book of Job, I propose to confine my remarks exclusively to its singular 

 dental apparatus, and such other matters as relate immediately thereto. 



The mouth of the hippopotamus, is one of the most capacious in the 

 animal world, and is armed with a set of teeth of the most powerful 

 description, adapted solely for cutting and bruising its food, which is of the 

 coarsest and rankest kind, and such as is found lining the banks of the 

 tropical rivers of Central and South Africa. 



The dental formula is as follows — 



Slipper jaw - 4 ( 1 — 1 

 — Canines < 

 lower jaw -4 ' 1 — 1 



(7—7 



Molars - - < = 38 teeth in all. 



6—6 



/ 



The molars evidently play but a secondary part in the economy of this 

 animal ; and a portion of them are described as " strictly false molars ;" that 

 is, the three molars of both jaws that succeed the canines, and which are 

 conical in form, having only one point. The posterior molars are armed 

 with two rows of points, which gradually wear down to a trefoil surface. 

 To man, the molars of the hippopotamus are perfectly useless. 



Incisor teeth, as the name imports, are the cutting instruments of the 

 jaw : and of these teeth, which are situated in the fore front of the mouth, 

 the hippopotamus possesses eight ; four in the upper jaw, which are short, 

 conical, cylindrical, and curved slightly inwards ; and four in the lower 

 jaw, cylindrical, straight, pointed and projecting forwards, the two centre 

 ones especially, termed lateral incisors, which are both longer, and larger, 

 than those next the canines. These incisor teeth are of some value in the 

 arts for their ivory. 



It so happens, that the teeth most highly prized by man, are those that 

 occupy the most prominent place in the dental economy of the hippopota- 

 mus : these are the canines, which may be described as " enormous 

 tusks," sharpened at their points, by mutual attrition of those in the upper 

 and lower jaw, into oblique " chisel-like edges." They are four in number, 

 two in each jaw ; the upper ones being short, slightly curved, rounded on 



* Some Naturalists distinguish between the hippopotami of South and* West 

 Africa, making two species— H. Capensis and H. Senegalensis — but the difference is 

 so small, that this division is for the most part rejected. 



