ZOOLOGICAL GARDENS, 
87 
The black-headed Ibis is closely allied to the sacred 
Ibis of Egypt, which was held in such veneration 
by the ancient Egyptians, that to have killed one, 
even by accident, subjected the offender to pain of 
death ; and there are no mummies in Egypt so numerous 
as those of the Ibis. There are generally two other species 
of Ibis exhibited in this House, viz*> the Glossy Ibis which 
has a very wide distribution, and the Scarlet Ibis which 
is limited to South America. 
The Tree-ducks are so called from their habit of 
building their nests in trees, and one Indian and two 
American species are exhibited. 
One of the most peculiar-looking birds in this aviary 
is the Darter or Snake-neck, a bird allied to the Cormo¬ 
rants, and not at all uncommon in Bengal. Its most 
remarkable features are its elongated, mobile, lithe neck ; 
and its attenuated head, but little broader than its 
neck; and its long pointed bill. There are many 
striking points in the anatomy of this bird, but there is, 
perhaps, none more interesting than the hair-sieve that 
occurs at the far end of the stomach and prevents the 
passage into the small intestines of the bones of the fishes 
on which the bird feeds. In order to understand its external 
differences from the cormorants, it may be compared 
with Graculus javanicus , a common Indian bird, in the 
adjoining compartment; where also will be found an 
example of one of the Gulls, a common species, which 
occurs along the sea-face of the Delta of the Ganges, and 
which, in the breeding season, assumes a sooty-black 
head and richly coral-coloured legs. 
In this House are also to be found some examples of 
one of the most interesting sections of the animal king- 
