430 On the Natural History of 
ra'of a kingdom. They are, consequently, voluminous in size, and 
their cost necessarily approaches to the price paid for a general Flo- 
ra of Britain. The two last have an intrinsic value, in original 
descriptions, &c. independently of their use as local lists merely. 
The Midland Flora, and that of Oxford and the adjacent counties 
(Walker), are further augmented by " Introductions to Botany ;" 
and the Flora of Devon, by repeating generic and specific characters, 
in two arrangements, is really two Floras under one cover. Lastly, 
the Flora of Northumberland and Durham is expanded into a hun- 
dred and forty quarto pages, (including cryptogamic plants), with 
double columns, although printed in a close small type, and desti- 
tute of descriptions or technical characters. The bulk of this work 
is greatly increased by the name of each species being followed by 
references usually to four or five works relating to British Botany ; 
ninety-nine in the hundred of such references not being at all re- 
quired in a local catalogue. The work, however, is really careful- 
ly got up, and is a valuable production ; although, taking it in our 
present light of a local catalogue only, much time and talent has 
been unnecessarily wasted on it. We mean, that the scientific 
public would have drawn more advantage from a cheap list or Flora, 
which might have been written with a quarter of the trouble, and 
published at a quarter of the price. After the preceding remarks, 
it is scarcely requisite to say, that we give the preference to the 
floral catalogues first mentioned, and would willingly limit all such 
works to fifty pages at the outside ; feeling assured that half this 
number Avould usually suffice, and that all additions go to increase 
the bulk and price in a much greater ratio than they can add to the 
usefulness or the circulation. Let it be remembered, however, that 
we speak only with respect to the general usefulness of such works 
to the public. When designed chiefly for local circulation, to be 
used as class works or other special purposes, change of plan may 
be necessary. 
III. On the S atural History and Relations of the family ofCuculidce 
or Cuckoos, rvilh a view to determine the series of their variation. 
By WILLIAM SWAINSON, F.R. & L. S., &c. (Continued from 
page 213.) 
The CUCULIN^E or Genuine Cuckoos. 
As the pre-eminent type of the whole family, a perfect ex- 
ample is seen in the common cuckoo. On examining this bird 
we observe the following external characters ; 1. the bill is consi- 
