CHARACTERS OF THE SUIB^. 535 



expiiiKsion observable in C/ueropsis. In the greater freedom of 

 tlie digits the latter genus stands nearer to the Suidte *. 



Tlie tail is short. Its base is broad Avith convex edges, but 

 its distivl half is thin, parallel-sided, strongly compressed, and 

 provided with stiff short bristles. It serves apparently merely 

 as a cover to the onus, and in the female of the genital orifice as 

 well. (Text-fig. 3:), B, 0.) 



The penis is quite siuiple, cylindi-ical for the greater part of its 

 length, and somewhat abruptly attenuated at the apex, the 

 orifice being terminal. The penis is like that of >Sus scrofa, but 

 has no spiral twist when retracted. 



Family SuiD^. 

 The Rhinarium. 



The general character of the rhinarium in the Suidje is well 

 known. It is a movable disk, the upper and lateral edges of 

 which project to a greater or less extent beyond the skin of the 

 muzzle. Its anterior moist surface is nearly flat, its upper 

 ])ortion being nearly naked, and the lower covered with 

 short, stifi", spai'se hairs. Tlie area below the nostrils is usually 

 wider than thfi area above them, and the edges are, generally 

 speaking, convex, although the lower is less curved than the 

 upper. The nostrils look straight forwards, and are set on each 

 side of the middle line of the disk some distance apart. They 

 do not extend to its lateral edge, the lateral narial slit being 

 absent or so short as to be practically negligible. Their inner and 

 upper edges are sharply defined, but the outer blends gradually 

 with the adjacent surface of the rhinarium. 



In most of the genera of the famil}^ — Sus, Fotamochcerus, and 

 Dicoti/lesf {Tayassu and Pecari) — the variation in shape and 

 structure is comparatively slight, and the differences shown in 

 the sketches may be individual and not specific oi- generic. In 

 nil these cases the median height is less than the greatest widtli 

 by aboxit one-fourth or less, and the sides from the widest points 

 a. little below the nostrils are inclined inwards and upwards in 

 a nearly straight line to the cmwed summit, and the distance 

 between the nostrils is more than one-third but le.ss than one-half 

 the median height. 



In an example of Sus scrofa the widest part is just below the 

 inferior edge of the nostrils, and the infero-lateral margin is 

 rather markedly convex, and the sides from the level of the 



* In the monnted specimen of Hippopotamus ampJiibins in the Natural History 

 Museum, the chiuiicters of the feet here mentioned iirc not so iippnrent. The 

 npproxininte equality between the four digits is seen, but there is a deep depression 

 between the second and third, making the feet look more like those of Choeropsis. 

 This, however, is probabl}- due to the shrinkage of the interdigital tissue with 

 drying, 



t For convenience I retain in this paper the old familiar name Dicoti/les for the 

 American Suida;. 



