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. Nostril 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 body 1. arrjulm, p. 3;Jl. 



Ventrals in six equal longitudinal rows ; 

 thirty-three or thirty-live scales round 

 the middle of the body 2. osliauyhnessyi, p. 392. 



Ventrals in four longitudinal rows ; 

 twenty-seven scales round the middle 

 of the body 3. quadrilineatus, p. 393. 



Ventrals in six longitudinal rows ; forty- 

 three scales round the middle of the 

 body; digits distinctly toothed iuferiorly 4. manicatiis, 'p. 393. 



IT. Nostril pierced in the suture be- 

 tween two plates 5. vertebniUs, p. 394. 



1. Prionodactylus argulus. 



Cercosaura (Pantodactylus) argulus, Peters, I. c. p. 184, ])1. i. fig. 3. 



Snoixt short ; body rather short. Tlie ordinary head-shields ; 

 frontonasal longitudinally bisected ; pra)frnntals 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 vcnti-als, round the middle 

 of the body ; thirty-one scales from the occiput to the base of the tail. 

 V^entrals large, in six longitudinal rows, the outer row smaller, and 

 twenty transverse rows. A pair of large prasanal shields, in front 

 of which is another, much smaller, pair. Limbs with large shields ; 

 hinder side of thighs gi'auulale. Seven femoral pores on each side 

 ( cj ). Tail above and on the sides with scales similar to the dorsals, 

 interiorly with a double row of large smooth scales. Ei'own 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 iuferiorly 



