280 
THE EEPTILES OF EGYPT. 
scales are modified to produce a noise when the folds of the body are rubbed against 
one another, as occurs also in Cerastes. The simulation by Dasypeltis of these characters 
of the poisonous snake might be said to be its protection, but, on the other hand, the 
resemblance of Echis to Dasypeltis might likewise be to its advantage! 
As is well known, it lives exclusively on the eggs of birds. On Plate XXXIX. it is 
represented in the act of swallowing a pigeon's egg, but fowls' eggs are even within 
its capacity. Dr. Andrew Smith 1 , writing in 1842, says : " The paucity and smallness 
of the teeth in the mouth are favourable to the passage of the egg, and permit of its 
progress without injury, whereas were they otherwise, many eggs, which have very 
thin shells, would be broken before they entered the gullet, and the animal in 
consequence would be deprived of its natural food when within its reach." After the 
egg has passed back behind the head into the gullet its further progress is arrested 
and the snake makes violent efforts to crush it by contracting its neck. The modified 
hypapophyses of the anterior thoracic vertebrae protruding into this part of the 
oesophageal tract and capped with enamel-like teeth now perform their function, and, by 
the egg being forced against them by muscular contraction of the neck, fracture the 
shell, the contents of which pass backwards to the stomach, while the crushed egg-shell 
is prevented from doing so by the gullet teeth. After all the fluid contents have been 
squeezed out of the broken-up shell the latter is ejected from the mouth as a pellet 
about 15 minutes after the egg has been swallowed. 
I have not been able to ascertain whether the natives have any name for this 
snake. The specimen sent alive by Mr. Birdwood simply bore the name " Snake of 
the Fayum." 
Measurements &c. ofD. scabra, Linn, (in millim.). 
Sex. 
Total 
length. 
Tail. 
Ven- 
trals. 
Anal. 
Cau- 
dals. 
Scales. 
Upper 
labials. 
Labials 
entering 
orbit. 
Sub- 
oculars. 
Prue- 
oculars. 
Relation 
of pi'ffi- 
oculars 
to 
frontal. 
Post- 
oculars. 
Tem- 
porals. 
Loreal. 
Locality. 
$ 602 
95 
230 
1 
49 
24 
8 
4&5 

1 
B. Ex. 
2 
3+3 

Fayum. 
It seems remarkable that a snake of this kind, so specialized as regards its food- 
supply, should have been unknown to the ancient Egyptians. There is no evidence, 
so far as I have been able to discover, that they were acquainted with it, unless the 
figure, said to occur on the monuments, of a hawk-headed serpent with an egg in its 
mouth may have been derived from some knowledge of it. 
1 111. Zool. S. Afr. pi. bnriii. 
