ISO NEW YORK ZOOLOGICAL SOCIETY. 



varying abundance, to the Gulf States and Mexico. In this 

 enormous extent of country local conditions have produced their 

 expected results. As we go south this deer becomes a smaller 

 and more delicate animal, the antlers simpler and lighter, until 

 a Florida or Mexican specimen placed beside one from Maine 

 or Canada would show a degree of divergence in size, color, 

 and antlers clearly sufficient to constitute a separate species. As 

 a matter of fact, these outlying types are recognized as sub- 

 species, and I greatly doubt whether a hunter starting in Quebec 

 or New Brunswick, and securing a continuous series of specimens 

 as he passed down through Maine and New England, through 

 the Adirondack's and Pennsylvania along the line of the Blue 

 Ridge to the Gulf States, and thence to Mexico, could at any 

 point in his travels find the locality where one group ends and 

 another begins. As he progressed, one type would fade into 

 another, new characters appearing in an ever-increasing percent- 

 age of individuals. If, by some convulsion of nature, the deer 

 of the Central States were destroyed and the Maine deer driven 

 into Florida or Mexico — and such migrations have been common 

 since terrestrial life first appeared — two valid species would exist 

 in Florida. The Columbian Black-tail dwindling to the north 

 into the Sitka deer furnishes a similar case. 



These examples are parallel in the case of the caribou. In- 

 dividuals taken from widely distant points on the Pacific 

 coast show widely dififerent characters. So do deer taken from 

 Maine, Florida, and Mexico. In the case of the deer, we know 

 that intermediate types exist, and yet different sub-species are 

 recognized from the localities just mentioned. In the case 

 of the caribou we do not know whether intermediate types 

 exist or not. If they do not exist, the question of the specific 

 distinction of the forms described in this article may be consid- 

 ered settled. If they are found to exist, their case will be analo- 

 gous to that of the \'irginia deer, and the so-called species will 

 fall to the rank of sub-species or local races. 



The distinction between a species and a sub-species is founded 

 on this very point. Several groups of animals, presenting char- 

 acters of a certain value, and without intermediate forms, con- 

 stitute as many different species. Groups of animals with the 

 same characters, but fading imperceptibly into one another, are 

 recognized as sub-species. Many types recognized now as sub- 



