552 ZOOLOG ¥.. 
grasping, one toe projecting backward, while the bill is horny, 
usually sharp—conical, according to Coues. Various as are: 
the shape of the wings, they agree in having the great row 
of coverts not longer than half the secondaries ; the pri- 
maries either nine or ten in number, and the secondaries: 
more than six. The tail, extremely variable in shape, has. 
twelve rectrices (with certain anomalous exceptions). There 
is but one common carotid artery, and the sternum is very’ 
uniform in shape. Their high physical irritability is co- 
ordinate with the rapidity of their respiration and circula-: 
tion ; they consume the most oxygen and live the fastest. 
of all birds (Coues). 
There are two groups of 
Passerine birds, differing in 
the structure of the lower 
larynx ; in the first. (Clama- 
tores) the vocal organs are 
more or less rudimentary, 
the species not being singers, 
while .in the second and 
higher division (Oscines) the 
lower larynx is so developed 
that most of the species ex- 
cel as singers. In the sing- 
ing birds the vocal apparatus 
Fig. 476.—Kingbird._From Tenney’s (syrinz), or lower larynx, is 
Booey. situated next to the lungs at 
the end of the windpipe, with a muscular apparatus formed 
of five or six pairs of muscles, whose action varies the 
tension of the vocal cords and narrows or widens the 
glottides, which are elastic folds of the mucous membrane. 
A fold of the tympanal membrane of the syrinx, called the 
membrana semilunaris, projects inward. 
Representatives of the Clamatores are the Acadian fly- 
catcher, the wood pewee, the pewee or phebe-bird, and the 
kingbird (Fig. 476). The ‘last, sometimes called the bee- 
martin, Coues tells us, destroys a thousand noxious insects 
for every bee it eats. The lyre-bird (Fig. 477) is also a. 
member of this group. 
