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 would 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 Natural History and Relations of the family ofCuculidoe 



or Cuckoos, with a view to determine the series of their variation. 



By William Swainson, F.R. & L. S., &c (Continued from 



page 213.) 



The Cuculin.se 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- 



