200 NOTES ON TWO SrEClMENS OF Sl'ITTING-SNAKES FKOM SOUTHERN EHODESIA 



Sir Harry Johnston, K.C.M.G., K.C.B., says in his work on George GretifeU and the 

 Gongo, 1908:— 



Vol. I. " There are in the Congo regiou at least seven examples of viperlne and coljra snakes whose renom 



/idge ■2'2S is fatal. 



page ilv ''Above the Nduuga Kapids the Congo (Isangila-JIauyanga portion) is jieut up in a gnsty windy trough 



Ijetween steep, sterile slopes. Here, as Stanley remarks, Nature has begrudged life, animal as well as 

 vegetable. The somewhat .sterile dow'n-country away from the river-banks abounds with snakes to a degree 

 unusual in Congo-land — chiefly spitting cobras (Naiii) and deadly tree cobras ( Dendraspis), Cnusus vipers and 

 jiuff-adders. 



fiitge !i'2S ■■ With regard to the reptiles of the Congo the poisonous snakes include many types that are common 



to the rest of West Africa. The genera Xaia (Cobras), Dcmlrunpis (Tree Cobras), Causas (Cape Vipers), 

 ISllix (puff-adders), Atlicris (Tree vipers), and Alrmianpis (Egg-laying vipers) are all represented, the last- 

 named by fourteen species. 



/tage^ii" "The reptiles of Fernando Po are almost all common to the adjacent parts of Africa .... there are 



twenty-two snakes. Of these, so far as is known, only three kinds are poisonous — the rhinoceros puff-adder 

 (£if.is ii'isiivni is), the Ciiiisu.i rhomhentus, and the tree cobra ( IJcndritspia nerjlectus or jnniemnii)." 



The same author, iu his work on Liberia, 1906, Vol. II., pjj. 807-11, writes as 



follows : — 



p,!ge si'7 " The Reptiles of Liberia, so far as is known, olfer no species restricted to that country in its geographical 



distribution, though there are here represented most of the forms peculiar to West Africa north of the Ecjuator. 



•' Amongst the long array of Snakes at least ten arc poisonous, though it is remarkable how very seldom any 

 death is reported to occur from suake-bite in this counti-y, or in any other parts of Africa, as compared with Asia, 

 Australia and America. 



page 808 " Cifif.sas elioinhr.atits is very connnon iu Lil)eria. just as it is thruughout Africa south of the Sahara. It is a 



small, slender vi])or, with the head distinctly marked off from the neck. The Caasus viper is only about two feet 

 in length, but very venomous and daugerous from its insiguitic;ant appearance and size. It is olive-brown in colour 

 with V-shaped brown marks along the back, and a reversed V or arrow mark on the top of the flat head. 



A'.^'f >*l" ''The I'ltiisiis viper, already referred to, has a habit (which may be observed when it is kept in captivity) of 



dribbling its venom from the points of the long fangs when it is angry and excited. This peculiarity has been 

 nnich noticed hy Eurojieans and natives in South and South-West Africa, where this little viper shares with the 

 much larger Cobra the nickname of " spitting snake." The Cobras, of course, are not connected with the vipers 

 at all. They are simply a gronji of colubrine snakes that have independently acquired the feature of a poison 

 gland and a perforated fang. They may be told at a glance from the average viper by the narrow jaws. The skin 

 on the sides of the neck in the common African form of Xaia huie is dilatable into a hood, but this feature is not 

 so striking as in the common Indian cobra or the hooded snake (Scpedon) of South Africa. 



"The West African forms of cobra are regarded as separate species (i.r. from the Indian) — X. niyrieollis, 

 from the black markings on the back of the neck spreading into a general black tinge, and X. melanolcuca, 

 iu which the general colouring is in bolder contrast of black and white. These cobras are fairl}' common in 

 Liberia, where they often attain a length of four to eight feet. Xaia niciricollis is not infreiiuently seen in 

 native villages, which it visits on account of the rats and other vermin that form its food. The snakes 

 frequent the thatch more especially, and do not generally interfere with human lieings unless first attacked. 

 Even then, instead of striking with their fangs, they seem to prefer to eject the venom by compression of the 

 muscles of the poison gland, so that, like the Caasus viper, this serpent also bears the nickname of " spitting 

 snake." I have never, myself, actually observed this ejection of the venom, nor, I believe, has the fact been 

 certified by any scientific observer ; but it is asserted to be the case all over Africa wherever cobras are 

 found. The natives say that the snake aims at the eyes, and that if the venom enters the eye it causes a 

 very severe inSammation, but nothing worse. One fact is certain (from my own observation) : that these 

 African cobras are very slow to strike with their fangs. I have once or twice nearly trodden on one, and 

 the snake has rapidly withdrawn to a safe distance, and then adopted an attitude of menace." 



