AMERICAN FROGS OF THE GENUS RANA. 435 



Vomerine teeth in short transverse or oblique series or groups 

 between the choanse or extending a httle beyond the level of their 

 posterior borders, close together or at least nearer to each other than 

 to the choanse.^ 



Head as long as broad, or a little broader than long, or a little longer 

 than broad, moderately depressed; snout rounded or obtusely or 

 acutely pointed, projecting more or less beyond the mouth, as long 

 as the eye or longer; canthus rostralis obtuse; loreal region oblique, 

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

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

 greater than the interorbital width, which equals i to f that of the 

 upper eyelid; tympanum very distinct, | to once the diameter of the 

 eye, close to the latter or separated from it by a space not more than ^ 

 its diameter. 



Fingers obtusely pointed, sometimes bordered by a feeble lateral 

 fold, first longer than second, or first and second rarely equal, third 

 as long as or longer than the mouth; subarticular tubercles moder- 

 ately large or rather small, moderately prominent. 



Hind limb moderate or long, the tibio-tarsal articulation reaching 

 the eye or the tip of the snout, or a little beyond, usually between the 

 eye and the tip of the snout, tubercle strongly overlapping; tibia 

 31 to 5| times as long as broad. If to 2 times in length from snout to 

 vent, as long as or shorter or longer than the fore limb or the foot. 

 Toes obtusely pointed, f to nearly entirely webbed, usually 2 phalanges 

 of fourth free, sometimes 1 or 3; outer metatarsals separated nearly 

 to the base; subarticular tubercles rather small, moderately promi- 

 nent; tarsal fold feeble or absent; inner metatarsal tubercle narrow, 

 more or less prominent or compressed, ^ to | the length of the inner 

 toe; outer tubercle absent or very small and indistinct. 



Skin of upper parts smooth or granular, with more or less prominent 

 longitudinal warts or glandular longitudinal folds on the back; a 

 prominent, narrow or moderately broad glandular dorso-lateral fold, 

 extending from above the tympanum to the hip or not quite so far; 

 the distance between the dorso-lateral folds, on the back, 4| to 6 times 

 in length from snout to vent; a glandular fold from below the eye to 

 the vocal sac or to above the arm; glandular ridges sometimes present 

 along the tibia. Lower parts smooth, belly exceptionally feebly 

 granulate, hinder half of thighs granulate. 



5 In the type of R. trilobata, a young specimen which I have examined in the 

 Paris Museum, there is a short furrow between the horns of the tongue, 

 such as I have observed in some R. esculent a. 



