MUSEUM OF COMPARATIVE ZOOLOGY.- 395 



27. Rallus ciegans. 31. Himantopus nigricollis. 



28. Rallus crepitans. 32. Sterna aranea. 



29. ?IL-ematopus palliatus 33. Rhynchops nigra. 



30. Recurvirostra amerieana. 



IV. Alleghanian Fauna. The Alleghanian Fauna has the Car- 

 olinian for its southern boundary. Its northern boundary, from the 

 ample data for its determination at the eastward, appears to nearly coin- 

 cide with the isotheral line of 65° F. It is, however, an extremely irreg- 

 ular line, with abrupt and deep sinuosities. Beginning on the coast to 

 the eastward of the Penobscot Bay, it sweeps first somewhat to the 

 northeast, nearly or quite reaching Bangor ; thence passing westward 

 and southward, it follows the northern boundary of the lowlands through 

 Southern Maine and Southern New Hampshire. In the Connecticut 

 valley it Vises farther to the northward, and in its southern descent 

 skirts the eastern base of the Green Mountains, passing to the south- 

 ward and westward of these highlands in Connecticut, and thence 

 abruptly to the northward. Skirting the eastern boarder of the Cham- 

 plain valley, it continues still northward to the valley of the St. Law- 

 rence as far as Quebec ; thence turning again southwestward, it passes 

 along the northern border of the lowlands east of the Lawrentian Hills 

 (including the valley of the Ottawa), and crosses the southern peninsula 

 of Michigan near the forty-fifth parallel ; continuing thence northwest- 

 ward it passes near Fort Ripley. Reaching the valley of the Red River 

 of the North, it turns abruptly to the northward, enclosing the lowlands 

 around Lake Winnipeg and embracing the valley of the Saskatchewan 

 and those of its northern and southern branches, passing westward 

 till it meets the higher plateau forming the eastern slope of the Rocky 

 Mountains. This may be considered as approximately the northern 

 boundary of the Alleghanian Fauna; the physical, climatic, and phyto- 

 zoological- character of the interior of British North America being at 

 present too imperfectly known to render it easy to determine definitely 

 the northwestern limit of the Alleghanian Fauna.* 



* As already stated, the mean temperature of the breeding season (May, June, and 

 July) has been taken as limiting the breeding range of the species. But this criterion 

 associates regions which have very different climatic peculiarities, "when the temperature 

 of the whole year is considered, the isotheral lines diverging more widely from the 

 isothermal or yearly lines in the interior than on the Atlantic coast. While in the 

 Winnipeg basin the summer heat is sufficient to ripen corn and to permit of the cultiva- 



