NATURAL HISTORY. 
13fi 
bird, that of the smaller sorts being generally found bigger 
than that of a goose. 
The Tropic Biro includes only three known species, 
which are all distinguished by a wedge-like tail, the 
two middle feathers extending a vast length beyond the 
others. 
The Common Tropic Bird is about the size of a wigeon. 
The length to the tip of the two long feathers is nearly 
three feet. The bill is three inches long, and red. The 
head, neck, and under parts of the body are quite white. 
The upper parts of the plumage white also, but marked 
with black lines. The two middle feathers of the tail mea- 
sure twenty inches, and project fifteen inches beyond the 
rest. It takes its name from being chiefly found within the 
tropics. It frequently flies very high, but generally attends 
upon the flying fishes in their escape from their watery ene- 
mies ; and they have now and then been found in calm 
weather supinely floating on the backs of the drowsy tor- 
toises. Their flesh is not good, but is sometimes eaten by 
the hungry sailors. 
On the Palmerston island there is a black-billed tropic 
bird; and at Mauritius there is a tropic bird with a bill 
and a tail of a beautiful rose colour. 
The Darter is distinguished by a peculiarly long and 
slender neck, and includes three species. 
The white-bellied Darter is scarcely so large as a mal- 
lard, but its neck is so long that it measures not less than 
two feet ten inches. The bill is three inches long, straight 
and pointed. The neck is covered with downy soft feathers, 
of a reddish grey ; the upper parts of the plumage are 
dusky black, dashed with white: the under parts pure 
silvery white. It is a native of Brazil, and is extremely 
expert at catching fish. 
The black-bellied Darter is the size of the common duck. 
The head, neck, and breast are light brown. The back, 
scapulars, &c. marked with stripes of black and white. The 
quill feathers, belly, thighs, and tail are deep black. The 
four toes are united like those of the corvorant. In the is- 
lands of Ceylon and Java it sits on the shrubs that hang over 
the water. In a country where people are so apprehensive 
of serpents, it often terrifies the passengers, by darting out 
its long and slender neck, which in their surprise they mis 
take for the attack of some fatal reptile. 
