304 ASSES. 



I think the foregoing facts are sufficient to prove that the 

 castors are not rudiments of the first digits. I have no 

 theory to offer respecting their origin. 



2. The ass has a tufted tail, somewhat hke that of 

 a cow ; erect mane ; and no forelock, The horse has a 

 bushy tail, drooping mane, and a forelock, when they have 

 been allowed to Q-row. The difference in the mane is 

 due to the length of the hairs of the part. In the horse, 

 the hairs of the tail grow long from the root of the dock. 

 In the ass, they do so only as they approach the end of 

 the tail. 



3. Veterinary anatomists state that the ass has five loin 

 vertebra (see p. 30) ; and the horse, six, unless in some 

 very exceptional cases when he may have five. If we 

 examine the skeleton of the mountain zebra (see PI. 29), which 

 is in the Museum of the R. C. S., Lincoln's Inn Fields, 

 we shall, however, see that it has six loin vertebrae. The 

 skeleton of the famous race-horse Orlando, which is in the 

 same building, has only five loin vertebrae. I have never 

 heard of an instance, in the domestic ass, of the number of 

 these bones exceeding five. I do not know their normal 

 number in zebras. 



4. In the horse, the lachrymal duct, which is the canal that 

 conveys tears from the eye, on each respective side, into the 

 nostril, has its opening near the inferior commissure of the 

 nostril and on the line of union between the dark-coloured skin 

 and the pink mucous membrane. In the ass and mule, it is 

 situated at the inner face of the outer wing of the nostril. 

 This orifice is sometimes double. 



5. In the ass, the false nostril extends higher up than in 

 the horse. 



