Ranidae 



Underparts light, more or less mottled with dark, yellowish 

 posteriorly. 



Measurements: Size below medium, i. e. length 2 to 2| inches. 

 Distance between nostrils greater than width of the head between 

 the eyes. Legs long, length to heel just equalling total length 

 of head and body. (Legs shorter than are those of Rana sylvatica.} 

 Tibia equal to the femur and equal to one-half the total length 

 of head and body. 



Structure: Skin smooth. Head pointed. Ear smaller than 

 the eye. Lateral folds not greatly elevated. Web large. 



Range: The distribution of Rana cantdbrigiensis is wholly 

 northern. It is reported from Illinois, Michigan, Wisconsin, 

 and Minnesota northward to Great Slave Lake on the west and 

 St. James Bay on the east. 



Rana cantdbrigiensis would be recognised at once as a species 

 closely related to Rana sylvatica, the Eastern Wood Frog. It 

 differs only slightly in colouration and general form. It can be 

 distinguished at once by the leg measurement; the leg to the 

 heel just equals in length the total measurement of head and body. 



This frog has the same delicacy of beauty, the same gentle- 

 ness and alertness of expression, possessed by the Eastern Wood 

 Frog. It would be surprising to find any great difference in its 

 habits. It is probably silent, except at the breeding-season, 

 and is more thoroughly a land frog than are most of the species 

 of Rana. 



Its relationship to Rana sylvatica is also shown by its 

 northern distribution, which provess ability to endure a lower 

 temperature than most frogs. (Rana sylvatica is the earliest frog 

 to appear in the spring in the northeastern United States.) 



West of the range of Rana cantdbrigiensis, that is, from the 

 Great Slave Lake to Alaska, inclusive, the representative of 

 this frog is a subspecies, Rana cantdbrigiensis latiremis Cope. 

 The leg measurement will always distinguish this frog from 

 the Northern Wood Frog. The western form has short, stout 

 legs, the measurement to the heel never being more than three- 

 fourths the combined lengths of head and body (length to heel 

 equals distance forward to eye.) There are a few other differ- 

 ences plainly visible; for instance, distance between the nostrils 



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