332 
ON THE CLASSIFICATION OF BIRDS. 
that at least they follow each other. The circular series 
cannot be closed more perfectly ; and thus we have an 
additional proof that the very errors of such men, if 
rightly used, wiU often afford instruction. 
(20’7.) In now attempting to trace the natural series 
of this group, the most difficult, and certainly one of 
the most confused, in the whole range of ornithology, 
we wish to l>e understood as confining our exposition 
to the primary divisions and genera only, without at all 
attempting to designate other types of form than those 
already enumerated. We have been constrained to 
show how little dependence the ornithologist engaged 
in this task can place in books ; so that nothing hut a 
personal examination of a large number of the foreign 
species wiU enable him to fill up those blanks he will 
still perceive in the series. We have been obliged, also, 
even in this preparatory arrangement, to reject the 
genera Noctua, Bubo, and Ulula ; and we still hesitate in 
admitting Symium, uncertain at present whether the 
brown owl of Britain is really one of the types of the 
genus Slritc. On the other hand, it has been absolutely 
necessary to designate the groups here named Scotiaptex, 
Scotophilus, Heliaptex, and Nyctipotes ; the characters 
of which, moreover, have this advantage, that they are 
drawn both from internal organisation and external 
aspect. The characters of the five genera will now be 
concentrated in the following table of the entire family. 
STRIGID^ — The Owls. 
Genera. 
1. Typical Group. Ears large, opcrculated ; no egrets. Stuix. 
•2. St^-typicaL Ears smaller, no operculum j egrets. Asio. 
Ears small \ no egrets or operculum ; disk 
imiiertect 
r Head small; claws feathered ; tail short. Nyctea. 
3. Aberrant. Head large ; claws naked • tail moderate. Nyctipetes. 
C. Head small ; claws feathered ; tail wedged. Sub.via. 
(268.) We know too little, both of the scientific and of 
the natural history of the birds composing these groups, 
to admit of their analogies being traced among other 
families, at least with that precision which is desirable. 
Nevertheless there are not wanting indications sufficiently 
