FROGS OF COLOMBIA — COCHRAN AND COIN 45 



terval equal to one-half its own diameter. Fingers moderate, with 

 large disks, with lateral ridges, free, first finger shorter than second, 

 which is equal to fourth, both of these reaching to base of penultimate 

 phalanx of third, the disk of which covers about one- third the tym- 

 panum; a small oval thumb pad present; a round palmar callus; 

 metacarpal tubercles scarcely developed. Toes one-third webbed, 

 rather short, third toe longer than fifth, its disk fairly large, reaching 

 to base of penultimate phalanx of fourth; disk of fourth toe covering 

 nearly one-half the tympanum and larger than that of third finger; a 

 weak, oval inner metatarsal tubercle and a smaller oval outer one; no 

 definite tarsal ridge; a pronounced skinfold on heel and knee. Body 

 elongate, in postaxillary region narrower than greatest width of head. 

 When hind leg is adpressed, heel reaches to center of eye ; when limbs 

 are laid along the sides, knee and elbow overlap; when hind legs are 

 bent at right angles to body, heels are separated. Skin of upper parts 

 resistant to abrasion, smooth (minutely pustular under the lens); 

 venter smooth; no glandular ridge above tympanum; no skinfold 

 across the chest; no external vocal sacs in the male. 



Dimensions. — Head and body, 27 mm.; head length, 9 mm.; head 

 width, 9 mm. ; femur, 12 mm. ; tibia, 12 mm. ; foot, 10 mm. ; hand, 7 mm. 



Color in alcohol. — Dorsum seal brown, the dorsolateral region a 

 slightly paler color; side of head and body also seal brown, becoming 

 wood brown on upper lip where some pale spots of wood brown appear 

 in the darker area; sides seal brown, merging irregularly with the 

 tawny-olive ventral color and lacking a light diagonal dorsolateral 

 stripe; throat faintly marbled with olive; belly with dark sepia spots 

 and reticulations on the tawny-olive ground; chest and lower femur 

 tawny-olive with scarcely any dark spots; upper femur, tibia, and 

 forearm with seal brown crossbars; knee olive; soles of feet and palms 

 of hands tawny-olive. No evidence of any well-defined black or white 

 lateral stripes. 



Remarks. — This frog has a proportionately longer femur than any 

 others of its genus in Colombia except Phyllobates bicolor (with which 

 the critical measurement overlaps very slightly — the critical range in 

 P. thorntoni being from 46.7 to 49.7 percent, and in bicolor from 46.1 to 

 46.8 percent). The heel reaches between the center of eye and the 

 nostril in all but one example, in which it reaches to the posterior 

 corner of the eye. The belly appears smooth at first glance, but under 

 the lens is seen to be pustular, and in one specimen it is faintly granular. 

 In adults the belly is heavily spotted or reticulated, and sometimes 

 three or four large light spots appear on the side of the belly well 

 below the groin. Often the chin and chest are spotted. 



The largest example (AMNH 14016), a female containing eggs, 

 measures 32.5 millimeters in length. 



