100 Trans. Acad. Sci. of St. Louis. 



small dark-colored spots. The notes of the male toad are 

 heard principally during the breeding season, and may 

 be given by the syllables ur-r-r-r-r. (Hay.) 



Family Hylidae. 



Upper jaw with teeth. Fingers and toes furnished with disks. The 

 fingers with or without webs. Basal portions of fourth and fifth toe 

 bound together by the integument. Teeth always on upper jaw; gen- 

 erally on vomers. Sternum with overlapping cartilages. Transverse 

 processes of sacrum more or less expanded. Urostyle attached to two 

 sacral condyles. Vertebrae procoelian. 



Three genera are represented in Missouri. 



Key to the Geneea or Missouri. 



Fingers without a web. Toes fully webbed. Digital disks small. 



Acris. 

 Fingers not webbed. Toes with little or no web. Disks small. 



Chorophilus. 

 Fingers webbed or not. Toes fully webbed. Digital disks larger. 



Hyla. 



Genus acris. 



Fingers free; toes webbed, the tips of the digits with small disks. 

 'Vomerine teeth present. Tongue broad, slightly excised behind, free 

 for one-fourth of its length behind. Tympanum indistinct. Sacral 

 process little expanded. 



'21. Acris gryllus LeConte. Cricket Frog. Savannah 



o* 



Cricket. 



Rana gryllus, Rana dorsalis, Hylodes gryllus, Acris gryllus var. crepi- 

 tans, Acris acheta, Acris gryllus hufonia. 



Description. — Form frog-like. Head elongate, snout acuminate, pro- 

 jecting beyond the lower lip. Vomerine teeth in two patches between 

 the choanae. Tongue broad, ovate, with or without a notch behind. 

 Males with a large vocal sac, which opens beneath the tongue. Tym- 

 panic disk rather indistinct. Skin of back smooth, or with small or 

 large tubercles. Belly and thighs granulated: throat smooth. Legs 

 long, the heel passing near or beyond the snout. Two large metatarsal 

 tubercles. Subarticular tubercles well developed. Fingers without 

 -webs; toes webbed to near the tips. (Hay.) 



Three variations of this frog have been recognized: 



