208 MR. G. A. BOULENGER ON 



Grayia ornata Bocage, Herp. Ang. p. 104 ; Bouleng. P. Z. S. 

 1909, p. 944, fig. 295. 



West Africa, from Cameroon to Angola. 



3. Grayia tholloni Mocquard, Bull. Soc. Philom. (8) ix. 1897, 

 p. 11 ; Bouleng. P. Z. S. 1909, p. 951, fig. 299. 



French Congo, Katanga, Uganda, Egyptian Soudan. 



4. Grayia c.esar. 



Xenuroplds ccesar Giinth. Ann. & Mag. IS". H. (3) xii. 1863, 

 p. 357, pi. vi. fig. C ; Bouleng. Cat. Sn. ii. p. 288. 

 West Africa, from Cameroon to the Congo. 



20. HOMALOSOMA. 



Wagl. Syst. Amph. p. 190 ; Bouleng. Cat. Sn. ii. p. 273. 



1. HOMALOSOMA LUTRIX. 



Coluber tutrix Linn. S. N. i. p. 375. 

 Homalosoma tutrix Bouleng. t. c. p. 274. 

 East, Central, and South Africa. 



21. Prosymna. 

 Gray, Cat. Sn. p. 80 ; Bouleng. Cat. Sn. ii. p. 246. 



Synopsis of the Species. 



Two postoculars ; frontal more than half width of head ; scales 



in 17 rows; ventrals 131-153 P. ambigua. 



One postocular; prsefrontal entering the eye ; frontal more 



than half width of head ; scales in 15 rows ; ventrals 167 P. bocagii. 



One postocular ; prefrontal separated from the eye hy the 

 prseocular ; frontal not half width of head ; scales in 15 

 rows; ventrals 145-163 P. angolensis. 



1. Prosymna ambigua, Bocage, Jorn. Sc. Lisb. iv. 1873, p. 218, 

 and Herp. Ang. p. 99, pi. xi. fig. 1 ; Bouleng. t. c. p. 248. 



Angola ; N. Rhodesia ; East Africa, from the Zanzibar Coast 

 to Zululand. 



2. Prosymna bocagii Bouleng. Ann. & Mag. N. H. (6) xix. 

 1897, p. 278, fig., and Ann. Mus. Congo, Zool. ii. 1901, p. 9, 

 pi. iii. fig. 4. 



Ubanghi. 



3. Prosymna angolensis, sp. n. 



Prosymna frontalis (non Peters), Bocage, Herp. Ang. p. 98, 

 pi. xi. fig. 2. 

 Angola. 



