22 



THE ATLANTIC SLOPE NATURALIST. 



esis, or generation by the females alone, 

 as illustrated in the aphis fly or plant louse. 

 This insect has the unusual method of 

 reproduction, whereby it produces several 

 successive generations of females (nine 

 according to some observers) after which 

 a generation of males and females appear 

 together and the peculiarity repeats itself. 

 But this insect, as well as others, keeps 

 its individuality, and insects rarely cross, 

 so far as known. These instances are 

 presented as variations from what we con- 

 sider standard, yet the peculiarity is con- 

 stant. 



In mammals the condition is well 

 known in the case of the horse and ass, 

 and their product, the mule. The off- 

 spring is infertile in the case of these two 

 animals, excepting in a few instances, and 

 from this well known example of infer- 

 tility, the infertile offspring of all cross 

 breeding are ordinarily called "mules." 

 Now the horse and ass are distinct spe- 

 cies, and infertility is the almost invariable 

 result in all cases of crossing of distinct 

 species, whereas the crossing of varieties 

 does not result in infertility usually. 

 For instance, the variety of men, or more 

 properly races, may cross and the 

 progeny is fertile, as is the product of 

 any and all varieties of dogs and horses. 

 This may be taken as quite conclusive 

 evidence that the horses of whatever 

 breed all came from a common source, 

 and as well, that the dogs all came from 

 a common orign. It is even said that 

 the dog and wolf may produce fertile 

 progeny, but that the offspring of the 

 dog and fox are infertile. 



Turning to the cat tribe, we find that in 

 different species the fertility in offspring 

 is in evidence. The common domestic 

 cat may cross with the Angora and get 

 fertile progeny. But then it may be 

 claimed that these are simply varieties of 

 common origin, so I will mention the 

 crossing of the Manx cat with the com- 

 mon cat. The Manx cat, as is well 

 known, has no tail, and is an undoubted 

 distinct species in this large family, and 

 yet it crosses with the common domestic 

 cat and the progeny are fertile. I have 



a case in mind where a Manx cat crossed 

 with a common cat in my native town. 

 The result was that of the litter, two 

 kittens were provided with tails like their 

 mother, and one was tailless like the 

 sire. It is fair to say that this is an in- 

 stance where different species have 

 crossed and produced fertile offspring. 

 But it may be added that some natural- 

 ists have shown that the Manx cat with 

 its lack of a tail is the result of domesti- 

 cation and breeding, which, however, I 

 do not believe. There is a breed of cats 

 in this country called "coon cats" which 

 are now being cultivated. I do not know 

 of their origin, but they are mentioned 

 here, as the ridiculous notion prevails 

 with the ignorant that they are the result 

 of a cross between the common cat and 

 the raccoon. Nothing could be farther 

 from the truth, as the two animals be- 

 long to different families, and there is no 

 evidence that crossing has occurred in 

 animals of widely separated species. 



The common domestic hog has been 

 known to cross with the wild boar of 

 Europe, and as well with the wild hog 

 of India, and the offspring have proven 

 fertile, but crosses of common swine 

 with the barbaroussa have proven in- 

 fertile, according to reports. The same 

 has been found to be the case with the 

 progeny of domestic hogs and the wart 

 hog of Africa, while the offspring of hogs 

 and peccaries has proven fertile. 



Among the large game animals of the 

 world, the American Wapeti or elk has 

 been crossed successfully with the fallow 

 deer, but the products proved infertile, 

 according to reports. The bison has 

 been crossed with amazing success with 

 the domestic cattle, and though the 

 progeny proved infertile in almost every 

 instance, still the products were remark- 

 ably docile and there are great numbers 

 being raised in the Union today as the 

 cross readily fatten and are tractable and 

 easy to care for and withstand hardships 

 better than do the range cattle. 



Among smaller animals, the common 

 mouse has been crossed with the white 

 mouse, and the result has proven fertile, 



