MULES. 253 



" mule" to be applied in a general as well as a special manner. 

 Thus we hear of mule canaries — crosses between the common canary 

 and an allied species. Crosses are not so uncommon as is generally 

 supposed. Thus : — 



(a) The one-humped and the Bactrian camel are crossed in Asia 

 Minor, and the result is a hybrid considered most useful and pre- 

 ferred on account of vigour of constitution. It is said that if the 

 dam be a dromedary and the sire a camel, the progeny works well • 

 but if the dam be a camel, the offspring is ill-tempered and in- 

 tractable. 



(b) The Bos taurus and Bos Indicus are very frequently crossed in 

 this country, and the progeny is said to be inferior in constitution to 

 the indigenous race, so it has not made much progress. However, 

 we have as yet little true knowledge concerning this cross. 



(c) In the Himalaya Bos grunniens, the yak, is frequently 

 crossed with the common ox of India ; and Moorcroft, after telling 

 us to use mules preferably to small horses for mountain journies, 

 says : " For the Himalaya, the beast that excels all in caution and 

 security is the jabu or mule from the yak of Tartary and the cow." 

 (Travels.) 



Among equines we have the following recorded : — 



(a) Ass with mare. 



(b) Horse with female ass. 



(c) Zebra with ass (Ann. du Mus., VII. 245, and IX. 223; F. 



Cuvier, Hist. Nat. des Mam., 1820; Geoffroy ; Gray's 

 Knowsley Gleanings). 



(d) Zebra with horse. (Ann. du Mus., XL 237-240). 



(e) Quagga with Arab mare (Phil. Trans. 1821, p. 90). 

 (/) Ass with Cutch wild ass mare. 



(g) Onager with Syrian wild ass (Animals in Gardens of 

 Zoological Society of London, 1883). 



(h) Ass-zebra with mare in Zoological Gardens, London (Darwin). 



(i) She-mule and ass. Zopyrus, Herodotus III. 153 long 151. 



Thus, what are usually described as species are very commonly 

 capable of crossing, and the old definition of species does not hold, or 

 we have been in error in breaking up camels, horses, cattle, and 

 other genera into various species. That the rigid interpretation of 



