6 ARKIV FÖR ZOOLOI. BAND 7. N.O 8. 



P. ambigua Bocage 



has six or seven upper labials, third and fourth entering the 

 eye; whitish or brown below. 



East Africa, Angola, Zululand. 



P. bocagei Blgr. 



f rontal reaching the eyes; prsef rontal entering the eye; one 

 postocular; six upper labials, third and fourth entering the 

 e^^e; rostral more angularil}" pointed and slightly turned up at 

 the end. 



Mbangi district. 



P. meleagris (Reinhardt) 



has onh^ one postocular; black above with a whitish terminal 

 dot on each scale uniform yellowish white below. 



West Africa. 



Finall}^ Moquard has described^ a species P. greigerti 

 from French Sudan but this is still more different than the 

 others having two internasals, tw^o prsefrontals etc. 



Some of these forms described as species, are of course, 

 more nearh' related to each other than others. The Prosymyia 

 from Lower Congo now described appears to be most nearh' 

 allied with P. meleagris, and to begin with I was inchned only 

 to regard it as a subspecies of this species, (and this proved also 

 låter to be the correct view). But when comparing the pre- 

 sent specimen with Reinhardt's original description,^ and espe- 

 cially his figures, I f ound the discrepanc}^ so great that I was near- 

 ly compelled to abandon this opinion and regard it as a new^ spe- 

 cies which is also more in conf ormity with the usual proceedings 

 among herpetologists in similar cases, probabl}' because we do 

 not know as yet how far the variation among the snakes can go.^ 

 Returning to this Prosymna from Lower Congo I must draw 

 the attention to the fact that if the present specimen is com- 

 pared with Reinhardt 's figures there are several other differ- 

 ences to be seen in addition to those revealed by the description. 



^ BuU. Mus. criiist. nat. T. XII. Paris 1906 p. 466. 



- K. Dansk. Vidensk. Selsk. Skr. Deel X. Kjöbenhavn 1843, p. 238. 

 Tab. T fig. 4—6. 



^ Such interesting investigations as Boul?:ngee,'s on the genus Grayia 

 (Proc. Zool. Soe. London 1909) are apt to throw a better light on the 

 oolour variations of sniilies. 



