64 



but will not stay there long. He also describes the note of triseriatus,. 

 which I have not heard. It is said to resemble that of the Cricket Frog, 

 although not so loud. It may be imitated by drawing a point strongly 

 across a coarse comb, holding them at the bottom of ajar and bringing 

 them rapidly to the top. The same authority says that the note is 

 uttered in the hottest part of the day. 



Family IX. RANID^. 



Upper jaw furnished with teeth. Vomerine teeth present or absent. 

 Transverse process of sacral vertebra little or not all expanded. Verte- 

 brae procoeolus. Ribs none. A large family, of some 20 genera and 

 about 250 species. They belong chiefly to the Old World. Our species 

 belong to the 



Grenus RANA, Linnasus. 



Rana, Linnieus, J 758, 6^, ed. x, 354; Boulenger, 1882, 37, 6; Cope,. 

 1889, 51, 393. 



Teeth on upper jaw and on vomers. Tongue free behind and notched. 

 Tympanum usually distinct, sometimes hidden. Fingers free. Toes 

 webbed. Outer metatarsals separated by a web. 



Contains more than a hundred species, living in all countries except 

 southern parts of South America and New Zealand. Cope assigns thir- 

 teen species to North America. 



Key to the E. U. S. Species of Rana. 



A. Without a black ear patch. 



Dorso-lateral dermal folds present ; heel reaching nearly to the muz- 

 zle or beyond it ; back with well defined dark brown, pale edged 

 oval or round spots. pipiens, p. 65. 



Dorso-lateral dermal folds large, with smaller ones between ; heel to 

 front of orbit ; tympanum one-half the diameter of eye ; brown 

 spots so large as to reduce ground color to a net-work of narrow 

 lines ; three phalanges of fourth toe without web, 



areolata circulosa, p. 68. 



Dorso-lateral dermal folds four ; the quadrate spots of back in rows ; 

 two phalanges of fourth toe free of web ; heel to front of orbit, or 

 sometimes to muzzle. palustris, p. 67. 



Dorso-lateral dermal folds present ; tympanum one-half size of eye, 

 or even larger than eye ; hind foot longer than tibia or femur ; 

 large dark spots on back. septentrionalis. Appendix. 



Dorso-dermal folds present ; skin of back rough ; tympanum nearly 

 as large as eye, or larger; toes webbed nearly to tips; heel not 

 reaching muzzle ; dark blotches on back ; size moderate. 



clamata, p. 69. 



