17, PRIONODACTYLUS. 391 
strongly keeled, imbricate, arranged in regular transverse series ; 
lateral scales small; ventral plates large, quadrangular, smooth, 
arranged in regular longitudinal and transverse series. A collar 
fold. Tail cylindrical. Femoral pores. 
South America. 
Synopsis of the Species. 
I. Nos¢ril pierced in the middle of a single nasal. 
Ventrals in six longitudinal rows, outer 
row smaller; twenty-nine scales, in- 
cluding ventrals, round the middle of 
THE "DOD Y ywivigug sch asendeo a actiiss a sleeytortns 1. argulus, p. 391. 
Ventrals in six equal longitudinal rows ; 
thirty-three or thirty-five scales round 
the middle of the body ............ 2. oshuughnessyi, p. 392. 
Ventrals in four longitudinal rows ; 
twenty-seven scales round the middle 
OL the body yates wits ee Sa Wh aes ses 3. quadrilineatus, p. 393. 
Ventrals in six longitudinal rows; forty- 
three scales round the middle of the 
body; digits distinctly toothed inferiorly 4. manicatus, p. 393. 
II. Nostril pierced in the suture be- 
tween two plates .............. 5. vertebralis, p. 394. 
1. Prionodactylus argulus. 
Cercosaura (Pantodactylus) argulus, Peters, J. c. p. 184, pl. i. fig. 3. 
Snout short; body rather short. The ordinary head-shields ; 
frontonasal longitudinally bisected; prefrontals very small, not 
forming a suture, separated by the anterior angle of the frontal ; 
parietals and interparietal subequal in size ; three occipitals, median 
smallest ; four supraoculars ; a loreal and a frenoorbital; temples 
shielded; six upper and as many lower labials ; chin-shields very 
large, one anterior and four pairs, the first two forming a suture, 
the two others separated by one or two rows of granules; two 
longitudinal rows of large transverse gular shields; five collar shields. 
Dorsal scales strongly keeled, very narrow ; lateral scales very small, 
keeled ; twenty-nine scales, including the ventrals, round the middle 
of the body ; thirty-one scales from the occiput to the base of the tail. 
Ventrals large, in six longitudinal rows, the outer row smaller, and 
twenty transverse rows. A pair of large preanal shields, in front 
of which is another, much smaller, pair. Limbs with large shields ; 
hinder side of thighs granulate. Seven femoral pores on each side 
(¢). Tail above and on the sides with scales similar to the dorsals, 
inferiorly with a double row of large smooth scales. Brown above, 
with five longitudinal rows of distant black dots; a black streak on 
each side, from the nostril to the ear, passing through the eye; two 
black lines on the side of the body, the lower bordered inferiorly 
