Page 518. 
366 ON THE ANATOMY OF PASSERINE BIRDS. 
pheeocercus, it appeared to me that the artery of the leg was the femoral ; 
but I should like to see more specimens before I can feel justified in 
disturbing any generalizations by using this single example. 
All acromyodian Passeres of species which I have examined, over 
one hundred in number, possess the sciatic artery, including Menwwra and 
Atrichia ; and the Tracheophone quite agree with them in this respect. 
Such being the case, it seems to me that from among the mesomyodian 
Passeres a small section may be divided off, including the families 
Pipride and Cotingide, in which a characterizing feature is the 
development of a femoral in place of a sciatic artery; and this being 
the case, Rupicola must be removed from the Cotingide. 
Although, as yet, our knowledge of the anatomical characters which 
are the bases of the minor divisions of the Passerine group is still so 
little advanced, nevertheless a rough sketch of the classification of the 
order, in which no attempt to fill-in details can be made, is quite 
within our power. 
To commence with Miiller’s character depending on the situation 
of the insertions of the syringeal muscles, Passerine birds fall primarily 
into two main sections, the AcRomyopI, in which the intrinsic muscles 
of the voice-organ are fixed to the end of the bronchial semirings, 
and the Mrsomyopt, in which they join them at or near their middle. 
The former group includes all the true Oscines, together with Menura 
and Atrichia ; the latter the Tracheophons, together with those Passeres 
included by Miller with the Picariz, as well as Pitta. 
The Mesomyodi fall into two groups, according to the situation of 
the main artery of the leg. Those in which the sciatic is the artery of 
the thigh may, because they therein agree with other birds, be termed 
Homeomeri; those in which the femoral artery is developed, from 
being in this respect abnormal, may be termed Heteromeri. 
Of the Homceomeri the Tracheophone of Miiller form a special 
well-marked section,—the rest, including the Tyrannide, Rupicola, 
and Pitta, forming a division which may be termed Haploophons 
until there is reason for further splitting them up. 
The following tabular arrangement expresses these views :— 
NORMALES. 
-ACROMYODI 
(Oscines). ue 
ABNORMALES. { oo } Menurine. 
richia. 
PASSERES.- os 
HETEROMERI. iectiet 
otingidee, 
| MESOMYODI. . 
Tracheophone. 
Tyrannide. 
Haploophone. 4 Rupicola, 
Pitta, 
HOM@OMERI, 1 
