Snakes of Tropical Africa. 331 



the upper surface of the head, but does not reach the vertical ; 

 two postoculars. Loreal not much longer than deep ; eight 

 low upper labials, of which the fourth and fifth enter the 

 orbit ; temporals rather irregular ; two pairs of chin-shields, 

 of which the posterior is only half the size of the anterior. 

 Ventral scutes 214. Upper parts and sides uniform brown, 

 lower parts whitish. Of the lateral lines of the head only 

 the anterior portions of the supraorbital lines are distinct ; 

 they converge on the anterior frontals. 



I have seen only one specimen of this species ; it came 

 from Fernando Po. It is young, 12 inches long, the tail 

 measuring 1^ inch. 



Boodon mentaliSy sp. n. (PI. XIX. fig. A.) 



Scales in 25 rows. Head much depressed, broad, as is 

 also the snout ; eye large. One preeocular, which is in con- 

 tact with the vertical ; two narrow postoculars. Loreal 

 longer than deep ; eight low upper labials, of which the 

 third, fourth, and fifth enter the orbit. Temporals 1 + 2 + 4. 

 Two pairs of chin-shields ; the shields of the posterior pair 

 are very narrow and entirely separated from each other by 

 the anterior. Ventral scutes 214. Upper parts light olive- 

 coloured, sides and lower parts white ; a very indistinct 

 yellowish band runs along the side of the anterior part of the 

 trunk. Two yellow lines on each side of the head, the supra- 

 orbital converging on the rostral shield ; the infraorbital is 

 rather irregular, straight, and not oblique, and covers the 

 greater part of the lower labial shields. 



I have seen only one specimen of this species ; it is young, 

 13 inches long, the tail measuring 2 inches. It came from 

 Damara Land. 



Causus Jacksonii, sp. n. 



Scales in 23 rows, only those of the upper series on the 

 hinder part of the body are keeled. The rostral shield is 

 turned upwards, with a slightly swollen upper edge as in 

 Causus 7'ostratus, in which, however, the shield is still more 

 prominent. In other respects the scutellation is very much 

 as in the other two species. Tlie anterior frontals are a 

 little longer than the posterior, and the area of the vertical 

 shield considerably surpasses that of the occipital. Nostril 

 between the two nasals and the anterior frontal. Loreal 

 square ; orbit surrounded by a ring of small and narrow 

 scutes. Six upper labials ; temporals 2 + 3, the two anterior 

 being the largest. Ventral scutes 146. 



