EXTERNAL ANATOSIY. CONCAVE TAIL. lO.'l 
stitute the Rasorial division of the Lanindat, this singular 
form of tail nearly pervades the whole group. We 
see it again in the rare Lewthrix fiircatus, Sw. 
{fig. 53.), which is the Rasorial genus of the chat- 
terers {Ampdulai). But we must look for its most 
striking and magni- 
ficent development in 
the Memira, where it 
is also combined with 
feathers of the fan- 
shaped structure. We 
may here remark that 
there is one solitary in- 
stance where these long 
exterior feathers are turned inwards instead of out- 
wards : this occurs in a humming-bird, figured by Ed- 
warils, as a native of Jamaica ; but we have never yet 
seen it, nor is a specimen known to exist at this time in 
any museum. 
(98.) 1 1. Boat-nliaped, or concave, tails, are still more 
extraordinary, and ap- 
pear restricted to two 
natural groups among 
the Sturnidcp, or star- 
lings, namely, the 
grackles of America (Qnixcalus), and the Lamprotor- 
nincE, or shining thrushes, of Africa. In the former 
we know at present but of one species ; but the whole 
of the latter appear to have tails, the sides of which, 
when expanded, are lient up like the sides of a 
boat, so as to leave the central part hollow and very 
concave : this appearance, however, is generally lost in 
the preserved specimens, so that these birds then appear 
to have oidy an ordinary rounded taih Of the pro- 
bable use of this singular structure we can form no 
correct idea. 
(99.) 12. Compressed, or erect tails, are nearly and 
obviously related to those which are boat-shaped, inas- 
much as both assume forms altogether different from 
