AMPHIBIANS. 57 



drigensis, is one of the most terrestrial of o\ir frogs and is usually 

 fouud in thick, wooded places, among dead leaves or moss. It is 

 very difficult to see because of the ])rotective coloration, the dark 

 brown or grayish coloring blending into the surroundings to such 

 an extent that one may almost step on individuals before seeing 

 them, and the black ear patch and the light line along the side of 

 the head also seem to be ])rotective. When disturbed the frog is 

 very active, leaping quickly away. It becomes very tame in cap- 

 tivity. The wood frog is among the first of the Ranidae to come out 

 in the spring. The hoarse clacking song of the males may be heard 

 during the latter part of March and early in April. The male has 

 no external vocal pouch, but the throat and the parts of the body 

 over the lungs expand. Unlike the males of other species, he floats 

 oi' swims in the water while croaking. The eggs are laid in ponds, 

 either in the woods or fields, in masses which are usually attached 

 to water plants. They are very small and are surrounded by a 

 gelatinous envelope. The time of development varies greatly ac- 

 cording to temperature. Eggs brought into the laboratory hatch 

 in four days, but the development of those left in the ponds is 

 much slower. Metamorphosis usually takes place some time during 

 May or June. The young tadpoles are very carnivorous, living 

 mostly on decaying animal matter in the ponds. 



Distrihutlon: Northern. "Reported from Illinois, ^lichigan, 

 Wisconsin and Minnesota northward to Great Slave Lake on the 

 west and St. James Bay on the east.-' (Dickerson, 190G, p. 212.) 



Michigan : Specimens in the University Museum from Keweenaw 

 (Isle Royale), Ontonagon, Baraga, Dickinson, ^Mackinac, Cheboy- 

 gan, Iosco, Huron, Livingston and Washtenaw Counties. The 

 writers have also examined specimens from Gratiot County. Re- 

 I)orted from Eaton County (Clark, 1902) ; Eaton, Kalamazoo, An- 

 trim, Yau Buren and Montcalm Counties (Gibbs, Notestein and 

 Clark, 1905 I ; Lenawee County (Kirsch, 1895) ; Ontonagon County 

 (Ruthveu, 1901:a) ; Keweenaw (Isle Royale), Baraga and Ontona- 

 gon Counties (Ruthven, 190G) ; Keweenaw County (Isle Royale) 

 (Ruthven. 1909) ; Cheboygan County (Ruthven. 1911) ; Huron 

 County (Ruthven, 1911a). 



KANA SEPTENTKIONALIS Baird. 



NORTHERN FROG. 



Dmcription: Body stotit. Head rounded, narrow in front. Eyes 

 large and close together. Skin smooth, slighth* granulated on ^sides 

 and posterior part of femUr. Feet fully webbed. Inner sole tuber- 



