64 BULLETIN 34, UNITED STATES NATIONAL MUSEUM. 



The cloiical fegiou is considerably swollen, and is broad and rounded, 

 or slightly emarginate behind. The distance from the groin to the pos- 

 terior end of the vent in this species is greater i)roportionally than in 

 any other of the genus so far as I have been able to determine. It is 

 contained in the distance from the snout to the groin but 3^ times. 



The tail is equal in length to the distance from the snout to the be- 

 ginning of the vent. It is much compressed and rather high. It has a 

 well- developed keel or crest, which begins immediately over the cloaca 

 and extends to the tip of the tail. The keel is sharp above, and is 

 bounded below on each side by a shallow groove. Interiorly the tail 

 is broadly rounded for its anterior third or more, and is traversed by a 

 median longitudinal groove. The remainder of its lower border is 

 compressed to a sharp edge. A transverse section of the tail, taken just 

 behind the cloaca, would form approximately an isosceles triangle whose 

 base would be about one half its height. Une-third of the distance back 

 toward the tip the height of the tail is three times its thicknesSo 



The limbs are well developed. The posterior are a little longer, some- 

 what stouter, and the foot broader than the same limbs of a specimen 

 of A. tigrinum that measures the same distance from the snout to the 

 end of the vent. They are also fully as long as the same limbs of a 

 specimen of A. punctatum that measures from snout to the end of the 

 vent three-fourths of an inch more than the specimen I am describing. 

 The toes are iiat, much like those of A. tigrinum. perhaps not so broad, 

 while they are not so slender as those of a specimen of A. -punctatum 

 now before me. Thej^ are provided with a narrow marginal autl basal 

 membrane. There are two distinct plantar tubercles. 



Measurements. 



Length : luchos. Lines. 



From snout to end of tail : .5 8 



From snout to gular fold 8.5 



From snout to lino joining axilko 1 1.5 



From suout to groin 2 3 



From snout to end of vent 3 



From end of vent to tip of tail 2 8 



From axilla to groin. 1 1.5 



From groin to end of vent 8.5 



Width of head at angle of jaw 7. 5 



Distance between anterior canthi 4. 6 



Interorbital space 3. 25 



Greatest height of the tail 5 



Thickness of tail at highest point 2 



Length of whole fore-leg 11 



Lower arm and hand U 7. 5 



Length of third finger 2. 5 



Hinder limb, total length 1 0. 05 



Lower leg and foot - - - - 1) 



Free portion fourth too 3 



Expanse of outstretched hinder limbs 2 5 



Distance between external nares 2. 6 



Distance between inner nares 3. 6 



