284 On the Track of an Animal lately found 



above the chord is sometimes as mucli as an inch and three quar- 

 ters. It is often somewhat pointed, and the highest part is not always 

 in the middle between the parallel side ridges (Fig. 4). The concave 

 side of the curve is always on the steeper side of the tranverse 

 ridges. 



There runs along the track a ridge intermediate between the two 

 parallel side ridges, (Figs. 3-4-5), and though it is not so conspi- 

 cuous as these, it is seldom altogether wanting, but appears to be, 

 most obscure when the transverse ridges, or rounds of the lad- 

 der, are straight. This intermediate ridge does not koep parallel 

 with the side ridges, but occasionally runs in sinuous sweeps from 

 within an inch and a half of one side (Fig. 5) to the same distance 



from the other ; sometimes 

 however, it runs nearly 

 parallel wdth the sides for 

 a considerable distance, 

 either in the middle or some- 

 what on either side of it. In 

 one of the tracks there is 

 in the course of the inter- 

 mediate ridge a sudden dis- 

 location of an inch and a 

 quarter (Fig. 3 towards the 

 top,) on the opposite sides 

 Fig. 4, One-uftli nat. size. of one of the transverse rid- 



ges. The course of the intermediate ridge appears in general to 

 coincide with the successive most salient parts of the transverse rid- 

 ges when these are curved, but this is not ahvays the case (Fig. 4). 

 The intermediate ri.'ge appears most conspicuous where it crosses 

 the transverse furrows, yet its crest or line of summit seems to 

 undulate with the ridges and furrows, though not to so great a 

 degree. 



The inner flanks of the side ridges appear to be continuously 

 even surfaces, making an angle of 155° with the plane of the inter- 

 mediate spaces, and against these sloping flanks the surface of the 

 transverse undulations forms a decided, though very obtuse set of 

 angles, just like waves rolling along an inclined plane in the direc- 

 tion of its strike. The side ridges are rounded at the top, and 

 while their exterior flanks are more precipitous than the interior 



