in the Collection of the British Museum. 415 



Xenocalamus hicolor. PL XIX. figs. A. 



The principal characters by which this interesting snake 

 may be recognized at once are contained in the generic dia- 

 gnosis, and may be completed thus : — 



The vertical shield is the largest shield of the head, six- 

 sided, with an obtuse angle in front and a pointed one behind ; 

 the occipitals are comparatively small, ovate shields, forming- 

 only a very short suture behind the vertical. The nostril is 

 situated between two shields, the anterior being very small, 

 the posterior elongate, similar in form and size to the pra3- 

 ocular ; supraorbital and postocular very small ; six upper 

 labials, the anterior very small, the third and fourth entering 

 the orbit, the fifth forming a long suture with the occipital, 

 and larger than any of the other labials, the sixth very small 

 again ; one large temporal ; five lower labials besides the small 

 anterior median shield ; the first pair of lower labials form a 

 suture behind the median labial ; the second small ; the third 

 very large, as long as the others together ; a single pair of 

 narrow lanceolate chin-shields. Ventrals 219. 



Upper parts uniform black ; lower parts and the two outer 

 series of scales uniform white. I have examined a single 

 specimen, 17 inches long (tail mutilated), found by Mr. J. 

 Chapman on the Zambeze. 



The three figures on PI. XIX. represent the head, of twice 

 the natural size. 



Geophis elaps (Gthr.). 

 Rhahdosoma brevifrenaticm, Jan. 



We have received this snake recently also from Pebas. 



Geophis latifrons. PL XIX. figs. B. 



Scales in seventeen rows. Ventrals 155 ; anal entire ; sub- 

 caudals thirty-six. Upper labials six, the third and fourth 

 entering the orbit ; two postoculars ; temporals 1 -|- 2 ; one 

 pair of chin-shields in contact with four labials. Vertical 

 very broad, broader than long, with the lateral edges short 

 and convergent ; frontals longest in their transverse diameter. 



Head and neck black, with a yellow ring across the pos- 

 terior half of the occipitals and the temporal shields. Body 

 encircled by ten pairs of black rings, each ring being as broad 

 as the red interspace. Each scale of the red interspace with 

 a black tip ; tail with two pairs of similar rings. 



One specimen has been sent from Pebas by Mr. Hauxwell, 

 a correspondent of Mr. Bates. It is 10 inches long, the head 

 being 4 lines, the tail 18 lines. 



