THE BIRDS OF AUSTRALIA. 
course of this work, I found that probably the close resemblance of the 
Australian bird to the type of Choriotis was not significant of real close 
affinity, but simply a case of convergence such as might easily occur in 
a group of this character. I therefore introduced the genus Austrotis for the 
Australian bird with the differential points noted, as : “ Differs from Choriotis 
(type C. arabs) in its shorter, broader bill : probably we have here a case of 
convergence, as the nostrils in Choriotis are placed at some distance from the 
base of the culmen, while in Austrotis they are very near the base ; the tarsus 
is more than three times the length of the middle toe in Choriotis, whereas 
in Austrotis it is less ; the wing-formulas in the two genera are different : in 
Choriotis the third, fourth, and fifth primaries are subequal and longest; 
the fifth primary in Austrotis is longest, the sixth being equal to the 
fourth and longer than the third.” 
In addition, in Choriotis the wing is less than twice the length of the 
tail, while the metatarsus is about one-third the wing-length. 
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