Sclater on the Systema Avium. 
33 
ployed in the ‘ Nomenclator ’ as still the most convenient to be 
adopted, and to place the Acromyodi abnormales of Garrod 
(which, being extra- American, were not included in the ‘No- 
menclator’) at the end of the Passerine series under the name 
Pseudoscines. The arrangement would then come out as fol- 
lows : — 
i. Oscines. 
ii. Oligomyodae. 
iii. Tracheophonae. 
iv. Pseudoscines 
} a. Atrichiidae. 
b. Menuridae. 
We thus get the advantage of having what are certainly the 
most anomalous forms of Passerine birds yet known at the end 
of the series. 
We must now approach the still more vexed question of the 
division of the Oscines into families. The difficulty here ob- 
viously arises from the fact that the Oscines are all very closely 
related to one another, and, in reality, form little more than one 
group, equivalent to other so-called families of birds. As, how- 
ever, there are some 4700 species of Oscines known, it is abso- 
lutely necessary to subdivide them ; and the task of doing this in 
the most convenient and natural way is not an easy one. 
Sundevall, who has certainly devoted more time and attention 
to the external characters of the Passeres than any other natural- 
ist of this century, in his last work (‘ Methodi Naturalis Avium 
disponendarum Tentamen,’ Stockholm, 1872) divided his “Os- 
cines laminiplantares ” (which are equivalent to the Passeres here 
considered, with the exception of the Larks) into six “Cohortes,” 
as follows : — 
i. Cichlomorphas .... 50 fam. iv. Certhiomorphse .... 3 fam. 
ii. Conirostres 15 “ v. Cinnyrimorphae .... 5 “ 
iii. Coliomorphas .... 15 “ vi. Cheiidomorphae . . . . 1 “ 
Sundevall’s characters are derived partly from the structure of 
the bill and partly from other points, and his six primary 
divisions seem to me to be very naturally conceived. On the 
other hand, Mr. Wallace’s well-known arrangement of the Pas- 
seres, first proposed in this Journal,* and subsequently followed 
in his great work on distribution, is based entirely upon the 
* Ibis, 1874, p. 406. 
