FROGS OF COLOMBIA — COCHRAN AND GOIN 357 



thigh rugose. External vocal pouch a longitudinally folded structure 

 that extends from a horizontal fold at level of angles of the jaws 

 posteriorly to another horizontal fold at level of the axillary region. 

 A well-developed horizontal dermal flap on each side of anus, each 

 flap about 2% millimeters in length and 1 millimeter in height; a 

 well-developed horizontal dermal fold on each heel. Tongue broadly 

 cordate, slightly free and slightly notched behind, its width about 

 four-fifths the width of mouth. Vomerine teeth in two minute, rounded 

 patches behind a line between the internal nares and separated from 

 them by about four diameters of an individual tooth patch; each 

 patch of teeth smaller than an internal naris; the tooth patches 

 separated on the midline by less than their own diameter. 



Dimensions. — Head and body, 27.5 mm.; head width, 9.1 mm.; 

 tip of snout to posterior margin of tympanum, 7.2 mm.; diameter of 

 eye, 2.9 mm.; diameter of tympanum, 1 mm.; hind leg (vent to tip of 

 longest toe), 40 mm.; hind leg (vent to heel), 27 mm. 



Color in alcohol. — To the naked eye the type gives the impression 

 of being uniformly creamy white. Under low-power magnification 

 the back and the dorsal surfaces of the limbs can be seen to be finely 

 sprinkled with red pigment. 



Variation. — When fresh the two females had more spotting on the 

 back than the three males. Both females had tiny, isolated, rusty 

 red spots scattered over the dorsum and the dorsal surface of the 

 shanks (after nine months in preservative). No such spots were 

 discernible in the males at that time, although in one male reddish 

 pigment cells could be seen in the skin of the dorsum under low 

 magnification (X 6.6). Other than the pattern mentioned above, the 

 skins of the specimens are uniformly creamy white. As in other pre- 

 served specimens of Sphaenorhynchus, the eye, with its black choroid 

 coat, stands out against the white skin. 



In no specimens of this species could be seen any green in the bones, 

 such as observed in some of the other species in the genus. 



All the specimens are uniform in having the fingers only about 

 one-third webbed and in having the toes fully webbed to the base of 

 the disks, except the fourth toe which has a margin of web extending 

 to the base of the disk. In all specimens the first finger is smaller in 

 diameter than the other fingers and seems to be twisted around so 

 that it approaches the condition of being opposable. This same con- 

 dition obtains in the other species of Sphaenorhynchus, and field ob- 

 servations on how these frogs use the hands are much to be desired. 

 All of the paratypes have a rudimentary pollex. The specimens are 

 consistent also in having the vomerine teeth in two tiny oval patches 

 that are separated from the choanae by about four or five diameters 

 of an individual patch. 



337-262—70 24 



