AMERICAN FROGS OF THE GENUS RANA. 419 



Vomerine teeth in small groups or short oblique series between the 

 choanse (rarely just behind them), a little nearer to each other than 

 to the latter, or close together. 



Head broader than long, much depressed; snout rounded, fully 

 projecting beyond the mouth, as long as the eye or a little longer; 

 canthus rostralis very indistinct; loreal region very oblique, slightly 

 concave; nostril equidistant from the eye and from the tip of the 

 snout or a little nearer the former; distance between the nostrils 

 equal to or a little greater than the interorbital width, which is I 

 to nearly once that of the upper eyelid; tympanum very distinct, 

 nearly as large as the eye in females, larger in males (up to If times the 

 diameter of the eye), close to the eye or narrowly separated from it in 

 males, 2 to 3 times its distance from the latter in females. 



Fingers moderate or rather long, sometimes pointed, sometimes 

 obtuse, first as long as or a little longer than the second, third longer 

 than the snout; a narrow round fold sometimes present along the 

 sides of the fingers; subarticular tubercles small, feebly prominent. 



Hind limb moderately long, the tibio-tarsal articulation reaching 

 the tympanum or the eye, the heels meeting or feebly overlapping 

 when the limbs are folded at right angles to the body; tibia 3 to 3| 

 times as long as broad, 2iV to 2^ times in length from snout to vent, 

 shorter than the fore limb or than the foot. Toes rather long, obtuse 

 or with slightly swollen tips, fully webbed, but the tip of the fourth 

 free; outer metatarsals separated to the base; subarticular tubercles 

 small; feebly prominent; no tarsal fold; inner metatarsal tubercle 

 elliptic, feebly prominent, i to f the length of the inner toe; no outer 

 tubercle. 



Skin smooth on back with small warts; a strong glandular fold 

 from the eye to the shoulder. 



Brown or olive above, rarely green, uniform or spotted or marbled 

 with dark brown or, very nearly, uniform blackish; limbs with or 

 without dark cross-bands; hinder side of thighs often marbled black 

 and yellow. Lower parts white, sometimes marbled with brown, or 

 trout brown, spotted with white (females) , or yellow (males) ; some- 

 times a black band along the posterior part of the thighs. 



INIale with internal vocal sacs and a retracting pad on the inner side 

 of the first finger. 



Skeleton very similar to that of R. csculcnia. Nasal bones moder- 

 ately large, in contact w4th each other or narrowly separated, separated 

 from the ethmoid, a small part of the upper surface of which is exposed ; 

 frontoparietals grooved along the middle and compressed behind. 



