409 



11. LlOCEPHALUS IRIDESCENS, n. Sp. (PI. XX. fig. B.) 



The upper surface of the head covered with scales, without distinct 

 shield ; shoulder and throat without any fold. Scales of the upper 

 parts distinctly keeled, of the belly nearly smooth. Above greenish- 

 brown, with a dorsal series of black angular transverse streaks ; a 

 black collar. 



Description. — The head is rather short and high, above shghtly 

 convex, with the interspace between the bony orbits very narrow, 

 and with the muzzle rather short, blunt, and rounded in front ; the 

 distance between the extremity of the snout and the anterior margin 

 of the eye is equal to the distance between the anterior angles of the 

 orbits. The nostril is directed upwards, round, situated more on 

 the upper surface of the head than on the side, and formed by a 

 tubular opening at the posterior extremity of a single small shield. 

 The eye is of moderate size, with round pupil and an upper and a 

 lower eyelid. The cleft of the ear is subelliptical, a little behind 

 the cleft of the mouth and in front bordered by some small promi- 

 nent scales. All the upper surface of the head is covered by scale- 

 like imbricate shields, the two hindmost of which (on the sides of 

 the occiput) are the largest ; two series of these shields cover the 

 space between the bony orbits, the roof of the orbit itself being 

 formed by a series of five shields, and by small scales anterioi'ly and 

 externally. Some of these head-shields exhibit feeble keels. The 

 rostral shield is very low, but broad, covering all the anterior margin 

 of the jaw ; four very narrow upper labials, above which is situated 

 another series of similar shields, the loreal region being irregularly 

 shielded. The temples are covered with scales similar to those on 

 the neck. The lower front labial is higher, but shorter, than the 

 rostral; five narrow lower labial shields, internally to which are two 

 other series of small oblong shields ; there are two diverging series 

 of broad shields arising from the posterior part of the front labial, 

 passing posteriorly into the ordinary scales of the throat ; all the 

 throat is covered with smooth imbricate scales, similar in size and 

 form to those of the belly. 



The trunk is subquadrangular, slightly depressed, and covered 

 with rhombic scales of moderate size, keeled, and arranged in series 

 which converge towards the vertebral line. There is a serrated and 

 rather low crest from the neck along the back, which is lost near the 

 middle of the tail. The scales on the belly form oblique series, and 

 are smooth or very indistinctly keeled. No prseanal pores, the 

 space before the vent being scaly like the belly. The tail is slightly 

 compressed and covered with scales, arranged and shaped like those 

 of the back, but rather more strongly keeled. The scales of the 

 extremities also do not differ from the others. The fore-leg reaches 

 to the loin, if laid backwards : the fourth finger is very little longer 

 than the third ; the second and fifth are considerably shorter, and 

 nearly equal in length to each other ; the first is the shortest. They 

 are smooth above, rough beneath, and provided with claws of mo- 

 derate strength. The hind-leg reaches rather beyond the anterior 



