516 



U.S. NATIONAL MUSEUM BULLETIN 288 



membrane not reticulate; interorbital distance about equal to width 

 of upper eyelid, which is relatively wide and distinctly wider than 

 distance between nostrils. Tympanum very distinct for a Centrolenella, 

 about one-fourth the diameter of eye, separated from orbit by a dis- 

 tance equal to one-fourth its own diameter. Fingers with no web 

 between first and second, a trace of web between second and third, 

 and the web between third and fourth extending to the proximal 

 one-third of antepenultimate phalanx of third finger and to the distal 

 end of antepenultimate phalanx of fourth; fingers 3-4-2-1 in order of 

 decreasing length; fourth considerably longer than second, just 

 reaching to disk of third which covers about half again the tympanic 

 area; no projecting rudiment of a pollex; no ulnar ridge; humeral 

 spine well-developed and prominent but not penetrating the skin. 

 Toes slightly more than one-half webbed, the web on fourth toe 

 reaching to middle of antepenultimate phalanx, third and fifth toes 

 subequal, disk of fourth toe V/% times the tympanic area; a distinct 

 oval inner and a smaller but equally distinct rounded outer metatarsal 

 tubercle; no tarsal ridge; no dermal appendage on heel. Body not 

 elongate, in postaxillary region a little narrower than greatest width 

 of head; when hind leg is adpressed, heel reaches to tip of snout; 

 when limbs are laid along the side, knee and elbow considerably 

 overlap; when hind legs are bent at right angles to body, heels overlap. 

 No patagium present. Skin of upper parts soft and thin, as is typical 



Figure 54. — Centrolenella johnelsi, holotype, MLS 432 (X 2). 



