CLEWS IN NATURAL HISTORY. 25 



three joints or " phalanges " (1, 2, 3) composing his third finger. These 

 joints are well known in ordinary life as the " pastern," " coronary," 

 and " coffin bones " ; and the last bears the greatly developed nail we 

 call the " hoof." 



Thus the horse walks upon a single finger or digit the third; and 

 it behooves us to ask what has become of the remaining five the high- 

 est number of fingers and toes found in mammals or quadrupeds ? We 

 find that, with the exception of other two the second and fourth fingers 

 the horse's digits have completely disappeared. The second and fourth 

 fingers have left mere traces, it is true, but it is exactly these rudimen- 

 tary fingers which serve as the chief clews to the whole history of the 

 equine race. On each side of the single palm-bone of the horse's great 

 finger, we see two thin strips of bone (one of which is represented at 

 m 2 Fig. 10), which veterinary surgeons familiarly term " splint-bones." 

 (See also Fig. 12 A, d). But these "splints" bear no finger-bones, and 

 the condition of the horse's "hand" or fore-foot is therefore seen to 

 be of most noteworthy and curious conformation. It may, indeed, some- 

 times happen that the small pieces of gristle or cartilage may be found 

 at the base of the splint-bones, and comparative anatomists incline to 

 regard these gristly pieces as the representatives of the first and fifth 

 fingers. But the ordinary condition of the horse's hand may be summed 

 up by saying that the animal walks on one well-developed finger the 

 third and possesses the rudiments, in the form of the "splint-bones," 

 of other two fingers, the second and fourth. These latter, it need hardly 

 be added, are completely concealed beneath the skin and other tissues 

 of the limb. In the hind-limb of the horse (Fig. 11), a similar modifi- 

 cation is observed. The thigh-bone {fe) and knee-cap (p) are readily 

 observed. There is but one toe the third ( l , 2 , 3 ) supported by a 

 single cannon-bone [nit 1 ) ; and there are likewise two splint-bones (one 

 depicted at m 2 ), representing the rudiments of the second and fourth 

 toes. The horse's heel, like his wrist, appears out of place, and is popu- 

 larly named his " hock." The shin-bone (t) is the chief bone of the leg, 

 and has united to it the other bone (ft) succeeding the thigh, named 

 the fibula, and which is seen in man's leg, and in that of quadrupeds at 

 large. 



To the eyes even of an unscientific observer, who sees the skeleton 

 of a horse placed in a museum, in contrast with the bony frames of 

 other and nearly related animals, the equine type is admittedly a very 

 peculiar and much modified one. In place of five toes, we find but 

 one ; and in the matter of its teeth, as well as in other features of its 

 frame, the horse may be said to present us with an animal form which 

 appears as a literal example of Salanio's remark that 



Nature hath framed strange fellows in her time. 



A person of a thoroughly skeptical turn of mind might possibly de- 

 mand to know the exact reasons for the assumption that the splint- 



