~ 
152 ON THE CLASSIFICATION oF “Bn : 
perpendicular rocks or buildings swith the grea es 
facility: others (Chetura Stev.), with less robust feet 
are compensated for the deficiency by being furnished 
with a very stiff and pointed tail, which serves as an 
additional support, when resting in such situations. 
In the long-winged swifts of India (Macropterya 
Swains.), all these characters are modified, and we see 
the swifts changed almost into the swallows. The two 
typical groups of the Fissirostres are thus united, and 
both may be characterised by a very short bill. The 
third group, as usual, contains three others, all exhibit- 
ing, more or less, a similar economy, but having the 
bill considerably more lengthened. , 
(172.) The Meropide, or bee-eaters, succeed the 
swallows. This family is confined to the warm regions 
of the Old World: one species, however, the Merops” 
apiaster, or European bee-eater, has occasionally strayed” 
to Britain. These birds annually visit Italy in flocks of 
twenty or thirty, and may be seen skimming over the 
vineyards and olive plantations with a flight much re~ 
sembling the swallow, though more direct and less rapid : 
their bill, however, is considerably longer and more 
gracile ; but this difference i is softened down by the inter-_ 
vention of the genus Lurystomus, containing the swallow 
rollers of India, Africa, and Australia, where this member 
is very short. To these succeed the true rollers (Coracias 
Lin.), which arrive in Italy at the same time with the 
bee-eaters, and associate also in small flocks. These two 
genera of rollers are so indissolubly united, that nothing 
but the strongest prejudice in favour of a preconceived — 
theory could ever have induced certain naturalists” 
(whose labours, in other respects, have been of much ad- 
vantage to science) to have placed them in two different 
orders. The whole structure of the rollers, their 
lengthened pointed wings, and their firm and often 
forked tail, at once induces the idea that they feed upon* 
the wing ; while their very short legs, scarcely longer — 
than their hind toe, might have shown their incapacit 
to alight and walk, like the crows, upon the ground: 
