NOTES ON SNAKES IN EAST AFKICA 
321 
had already been digested from the skull of the rat which had 
been swallowed eight hours previously. 
During their six months’ captivity they only once cast 
their skins and appeared in fresh clean olive-green coats. 
All the young mambas under 6 feet which the writer has 
kept have been of a bright leaf-green colour, those over 6 feet 
of an olive tone. A reasonable theory is that as they increase 
in size and give up their arboreal habits their colour becomes 
black ; certain it is that there is no detectable specific difference 
between the so-called Green and Black Mamba. 
The species just referred to is the common South African 
Mamba ( Dendraspis angusticeps), which ranges over Central 
and East Africa, having been taken at Tanga and Mombasa ; 
two other species are known in East Africa, one of which is 
doubtful, since it rests upon a single specimen collected in the 
Kilimanjaro region and called Dendraspis Sjostedi. Jameson’s 
Mamba ( Dendraspis Jamesoni), on the other hand, is as common 
as the South African species ranging over the whole of Tropical 
Africa and Angola. The writer has examined a number of 
specimens which were shot in trees in the Yala river district. 
It is a matter of surprise to many persons to learn that 
there are cobras in East Africa, and in many places — Nairobi 
in particular — the common Black-necked Cobra ( Naia nigri- 
collis) is erroneously called the Black Mamba. Whereas 
mambas have only a very limited power of flattening their 
necks, cobras when startled or enraged will spread a hood 
two to three times the normal diameter of the neck. 
The colour of the Black-necked Cobra at Nairobi is 
frequently olive- green or brown, with yellow bars on the throat; 
sometimes, however, as in all the Morogoro specimens yet 
seen, it is a lead-colour or slaty-black, in which case the throat 
is barred white or pink. At Longido, however, a beautiful 
salmon-pink is the normal colour of this snake with or without 
black spots. Anyone unacquainted with the variable colour- 
ation of reptiles could be forgiven for supposing it to be an 
entirely different species. 
On one occasion at Longido a corporal asked the writer 
if he could tell him the name of a terra-cotta snake. He 
said ‘ It is harmless, I think, because when I found it under 
