8 



nomial system of Linnaeus, and by adding a third term as name of the 

 subspecies to make it a trinomial one. Wherever a three-term name 

 is used, it is that of a subspecies of the original binomial form. The first 

 specimen described, or the first specimen to which a name has been at- 

 tached, is regarded as the so-called " Type " form. Therefore, in dividing 

 a species into subspecies the form which was first named as a species 

 becomes automatically the type race, and its subspecific name is formed 

 by a repetition of its specific name. Thus the American Robin that was 

 first described and specifically named by Linnaeus in 1766 as migratorius 

 when mentioned subspecifically in distinction from the Southern Robin or 

 the western one becomes Planesticus migratorius migratorius. The Western 

 Robin first separated from it by Ridgeway in 1877, was named by him as 

 Planesticus migratorius propinquus, and the Southern Robin by Bachelder 

 in 1900, is Planesticus migratorius achrusterus. In practice,where the generic 

 or specific names are evident from the context, it is customary to indicate 

 them by initial, as P. migratorius, or P. m. migratorius. 



Subspecific varieties are divisions of the species and, except in special 

 lines of work, or where special exactitude is necessary, of minor importance. 

 As these subspecies are also often based upon points of difference only 

 perceptible to the most experienced observers, they generally lie outside 

 the sphere of interest of the average amateur observer. 



GEOGRAPHICAL DISTRIBUTION. 



The broader facts of the geographical distribution of life are patent 

 to the most casual observer. The primary divisions of distribution, the 

 Tropics, Temperate, and Arctic zones are obvious, but closer study shows 

 that within these broad associations minor and less obvious ones can be 

 detected. In America, north of the gulf of Mexico, there are three life 

 regions, roughly following the above, called the Tropic, the Austral, and 

 the Boreal regions. These are subdivided into life zones each characterized 

 by its own peculiar assemblages of plants and animals. 



The Tropic region is sufficiently characterized by name and need be 

 only mentioned. 



The Austral region corresponds roughly to the popular geographical 

 conception of the Temperate zone. It is divided into three life zones, 

 the Lower Austral, the Upper Austral, and the Transition zones. The 

 Lower Austral might be designated as subtropic and extends north includ- 

 ing the gulf and the south Atlantic states, not occurring in Canada at all. 

 The Upper Austral is the first that we are directly interested in in eastern 

 Canada, it merely crosses the border on the lake Erie shore and includes 

 the famous Niagara fruit belt. The frequent or regular occurrence of 

 numerous southern species on Pelee point in Essex county, Ontario, marks 

 the strongest development of this zone in the Dominion. It slightly touches 

 our southern boundary again in Saskatchewan and perhaps some of the 

 warmer valleys running into southern British Columbia. The northern- 

 most Austral or Temperate life zone is the Transition zone which includes 

 the greater part of the more highly cultivated areas of Canada. It occupies 

 the shores of the bay of Fundy, the upper St. Lawrence river, southern 

 Quebec and Ontario, the lower sections of the prairie provinces, and a 



