280 COLUBKID^. 



the eye ; five lower labials in contact with the anterior chin- 

 bhields, which arc as long as the posterior. Scales in 21 rows, all 

 strongly keeled. Yentrals 116-120; anal divided ; subcaudals 88. 

 Grey above, with three longitudinal series of black spots, which are 

 confluent into longitudinal streaks on the sides of the head and on 

 the nape ; the middle row of spots largest ; ventrals grey, with a 

 yellowish streak in the middle, or yellow with blackish spots. 



Total length 410 millim. ; tail 150. The specimen in the collec- 

 tion measures 350 millim. without the tail, which is injured. 



Venezuela and Colombia. 



a. c? (V. 116; C.?). Rosaiio de Cucuta, Colombia. Mr. Webber [O.J. 



11. Helicops polylepis. 



Helicops polylepis, Guntli. Ann. ^ Mag.N. H. {?>) vii. 1861, p.*426. 

 Tachynectes cbrysostictus, Cope, Five. Ac. Philad. 1862, p. 71. 

 Plehcops spixii, Jan, Arch. Zoul. Anat. Fhys. iii. 1865, p. 249, and 

 Icon. Gen. 28, pi. ii. fig. 2 (1868). 



Eye rather small ; rostral visible from above, in contact with the 

 internasal; frontal twice as long as broad, as long as or a little 

 longer than its distance from the end of the snout, as long as or a 

 little shorter than the parietals ; loreal trapezoid ; one prte- and 

 two postoculars ; temporals 2 + 2, 2 + 3, or 1 + 3; eight upper 

 labials, fourth or third and fourth entering the eye ; five or six 

 lower labials in contact with the anterior chin-shields, which are as 

 long as the posterior. Scales in 23 or 25 rows, a;ll keeled, the keel 

 on the outer row feeble. Ventrals 124-138 ; anal divided ; sub- 

 caudals 76-84. Brownish or olive-grey above, with blackish spots 

 disposed in five alternating rows, the middle ones largest ; blackish 

 beneath, with round yellow spots. 



Total length 430 millim. ; tail 130. 



Brazil, North-eastern Peru. 



a. S (Sc. 25 (26) ; V. 133 ; Upper Amazon. (Tvpe.) 



C. 82). 

 h. Hgr. (Sc. 23 ; V. 124 ; Peruvian Amazon. Mr. E. Bartlett [C.]. 



C. 79). 



15. HYDR^THIOPS. 

 Hydrtethiops, Giinth. Ann. ^ Mag. N. H. (4) ix. 1872, p. 28. 



Maxillary teeth 20-22, increasing in size posteriorly ; mandi- 

 bular teeth decreasing in size posteriorly. Head slightly distinct 

 from neck; ej^e small, with round pupil; nostrils directed up- 

 wards, pierced between two nasals ; a single internasal. Body 

 cyhndrical ; scales striated and keeled, with apical pits, in 23 rows ; 

 ventrals rounded. Tail moderate ; subcaudals in two rows. Hypa- 

 ])ophyses developed throughout the vertebral column. 



Tropical Africa. 



