ON THE ANATOMY OF PASSERINE BIRDS. 355 
In one respect he made a retrograde step, because he did not lay suffi- 
cient stress upon the value of Nitzsch’s work; and this was that he 
united the mesomyodian Passerine birds which are not tracheophone 
with those families which constituted the more expanded “ Passeres” 
of Cuvier and with the Scansores, wavering between the two classifica- 
tions, which may be expressed, with the employment of the term intro- 
duced above, as follows :— 
1. Passzres Acromyopt (Oscines). 1. PasserEs Acromyopi (Oscines). 
2. PassErEs MesoMyopI TRACHEOPHONI. 2. PICARIZ. 
3. PIcaRIz. a. Passeres mesomyodi 
a. Puasseres Mesomyodi non- tracheophoni. 
tracheophoni. 6. Passeres mesomyodi non- 
&e. e tracheophoni. 
From the above remarks it is evident that Miiller was led to lay 
too great stress upon the nature of the syrinx as a distinctive feature 
of the Passeres; and although Nitzsch was unacquainted with the 
existence of the mesomyodian voice-organ, there can be scarcely any Page 508. 
doubt that had he lived subsequently to Miiller he would never have 
separated its possessors off from their oscine allies, considering that he 
had fundamental palatal and pterylographic characters to fall back upon. 
The investigations of Macgillivray* and others have made it evi- 
dent that colic ceca (of small size) are present in all true Passerine 
birds ; and this fact, when correlated with the universal presence of a - 
~ nude coccygeal oil-gland, has led met to place them in near relation- 
ship with those other Cuvierian Passeres (the Cuculide excepted) in 
which the oil-gland is nude and ceca coli are always present—away 
from the remainder of his group, in which no ceca are developed and 
the oil-gland is tufted. The Passeriformes and Piciformes thus defined, 
all wanting the ambiens muscle across the knee, are included in my 
major division of the Anomalogonate. 
Taking the summation of the characters above referred to, in asso- 
ciation with others too well known to require special mention, the 
PassERES may be defined as those Anomalogonatous birds with the 2nd, 
8rd, and 4th toes of the foot directed forwards, and the hallux back- 
wards, in which the flezor longus hallucis muscle is independent of the 
flexor perforans digitorum, the colic ceca are short, the oil-gland nude, 
at the same time that it is of a characteristic shape, and the palate 
eegithognathoust. 
Among the Anomalogonate there are three toes directed forwards 
in the Bucerotide, Alcedinide, Coliide, Upupide, Coraciine, Momo- 
- 
: 
* “ Audubon’s Ornithological Biography,” 1838. 
t “ Proceedings of the Zoological Society,” 1874, p.119. (Supra, p. 217). 
{ Professor Huxley, ‘ Classification of Birds,” “ Proceedings of the Zoological 
Society,” 1867, p. 456. 
ay eer 
