318 Illinois State Lahoratonj of Natural History. 



4 '(3). No teeth 5. 



5 (6). No parotid. Omosternum wanting, clavicle and 



precoracoid sometimes wanting. Transverse pro- 

 cesses of sacrum expanded Engystomid.*:. 



6 (5). Parotid present. Sternal arch with clavicles, pre- 



coracoids and overlapping cartilages; omosternum 



wanting Bufonid.^. 



7. With teeth. Sternal arch with overlapping carti- 

 lages ; omosternum and sternum present. Trans- 

 verse processes of sacrum expanded Hylid.i-:. 



Family RANIDiE. 



No parotids. Fingers and toes generally without discs ; 

 the former without webs, the latter webbed ; basal portions of 

 fourth and fifth toes not bound together. Teeth on the upper 

 jaw, and generally on vomers also. No fontanel between pa- 

 rieto-frontals. Omosternum and sternum present. Coracoids 

 expanded, in contact with each other and narrowly separated 

 from the precoracoids by cartilage. No epicoracoids. Trans- 

 verse processes of sacrum subcylindrical. Urostyle articulated 

 to two sacral concavities. Liver with three lobes. 



A large and widely distributed family, including many 

 large species. It is represented in Illinois by the single genus 

 Rana. 



Rana, Linn. 



Linnams, Systema Natune. ed. 10, 1758, 1., p. 'ilU (S. Garman). 

 Hoffmann, Bronn's Thier-Ueich, VI., Aniphibien, p. 018. 

 Holbrook, N. A. Ilerp., IV., p. 77. 



Fingers and toes very slightly or not at all expanded at 

 their tips, the former without webs, the latter more or less 

 webbed. Tongue wide, free and deeply excised behind. Tym- 

 panum distinct. Skin smooth or slightly tuberculate. Gland- 

 ular folds present or absent. Vomerine and maxillary teeth 

 present. No fontanel between the parieto-frontals. Males 

 with two lateral vocal sacs. 



This genus includes all the large active frogs of swamps 

 and meadows. Seven species occur in the State. 



