SVRINX 939 
are attached to the dorsal and some to the ventral ends, those ends 
being, so to say, equally treated; this form comprises the SUB- 
OSCINES (p. 921) and OSCINES; and 
(2) Passeres anisomyodi, in which the muscles are unequally 
inserted, either in the middle, or upon only one or the other, 
dorsal or ventral, end of the semirings; this form comprises the 
SUBCLAMATORES (p. 921) and CLAMATORES. 
In this way we can arrive at a natural classification of the 
Passeres, and avoid the obviously illogical shortcomings which result 
from attempts to sort them into two groups by the application of 
two distinct taxonomic principles, one being the number of the 
muscles and the other the mode of their insertion, in addition to 
the over-estimate of the tracheophonous type. 
The following list shews the number of muscles attached to the 
lower end of the Trachea or to the Syrinx (except the tracheo- 
clavicular and sterno-tracheal muscles) in various groups of Birds. 
I. Trachea and Syrinx devoid of muscles :—Casuarius, Dromxus, 
Apteryx, Struthio, most Steganopodes, Ciconiide, Cathartide and some 
Galline. This is not a primitive feature, but one brought about 
by loss. 
II. One pair of muscles inserted on the distal end of the 
Trachea :—Anseres, with Pulamedea, Scopus, Limosa, most Galline, 
Columbex, Pteroclidx, Opisthocomus, Rhamphastidx, Bucconidx, Momo- 
tidx, Todidx, Cypselus, some Pteroptochide and Formicariide. 
III. One pair of tracheo-bronchial muscles, arising mostly from 
the Trachea and attached to one or more of the bronchial semirings : 
—Thea, Sphenisci, Colymbus, Podicipedidx, Phalacrocorax, Tubinares, 
Ardeidx, Phenicopterus, Ralli, Grues, Limicolx, Laridx, Alcidx, Mega- 
cephalon, Lophortyx, most Falconidx, Cuculidx, Coraciide, Upupide, 
Coliidx, some Trochilidx, Pict, Capitonidx, Todidx, Striges, Caprimulgi, 
some Pteroptochidx and Formicariidx, Conopophagidex, Cotingidex, Pittidx, 
Philepittide, Eurylenide, various Pipride and Tyrannidz. 
IV. Two pairs of short tracheo-bronchial muscles :—Gallinago 
cxlestis, Falco, some Trochilidx, various Pipride and Tyrannide, 
Dendrocolaptide and Furnarudx, and Atrichornis—the last having 
one pair inserted dorsally and the other ventrally, and being there- 
fore diacromyodian. 
V. Three pairs :—Psittaci, with tracheal and tracheo-bronchial 
muscles; Menura and Poodytes,! with two dorsal and one ventral 
tracheo-bronchials. 
VI. Four pairs or more :—Grallina, with two dorsals and two 
ventrals ; Prosthematodera, with two or three dorsals and two ventrals. 
1 This is the Sphenwacus of Gould and other writers ; but the type of that 
genus is a South-African species which I can scarcely believe to be nearly allied ; 
I have therefore adopted the generic name which applies to the Australian form. 
The species I examined seems to be P. galuctodes. 
