Snakes of Tropical Africa. 329 



to my Boodon mentalis -J but this has 25, and not 21 or 23 

 scales, as Schlegel says. In short, the true Boodon geo- 

 metricus is unknown to me. 



The following table may assist in the discrimination of 

 these species : — 



I. Two pairs of cliiu-sluelds, the shields of the posterior pair iu contact 

 with each other, 



A. Scales in 23 rows. 



1. One anteocular. 



a. The anteocular reaches to the upper surface of the head ; 

 abdomen yellowish along the middle, slate-coloured on 



the side West Africa (Old Calabar and 



Ashantee) : B. ventralis, 



h. The anteocular does not reach to the upper surface of 

 the head j abdomen uniform dusky brown. 



Seychelle Islands : B. seychel- 

 lensis. 



2. Two anteoculars East Africa (Lake Tanganyika 



and Mombas) : B. bijn'cs- 

 ocularis. 



B. Scales iu 25 rows ; lower parts uniform whitish. 



Fernando Po : B. poensis. 



II. The chin-shields of the posterior pair are separated from each other 

 by the anterior pair, and do not meet in the median line ; scales in 25 

 rows Damara Laud : B. mentalis. 



Boodon ventraliSf sp. n. (PI. XVIII. fig. A.) 



Scales in 23 rows. Head moderately depressed ; snout 

 not very broad ; eye small. One prgeocular, which may or 

 may not reach the vertical ; two postoculars. Loreal longer 

 than deep ; eight low upper labials, the fourth and fifth 

 entering the orbit. Temporals 14-2 + 3. Two pairs of chin- 

 shields, the posterior pair about two thirds of the anterior. 

 Ventral scutes 205 or 207. Upper parts of a uniform slate- 

 colour, which colour extends on the abdomen, covering on 

 each side about one third of the ventral scutes, the middle 

 third only of the abdomen being of a yellowish-white colour; 

 lower part of the tail light slate-colour. Head with two nar- 

 row well-defined yellow lines on each side, the two supra- 

 orbital lines converging on the rostral shield. 



This is a West-African species and readily recognized by 

 the coloration of the abdomen. I have seen six specimens, 

 three being from Old Calabar and two from Ashantee. The 

 largest is 32 inches long, the tail measuring 5 inches. One 

 specimen had swallowed a rat. 



