274 Mr. H. Seebohnr's Corrections of 



disallow the claims of many species to be considered new. 

 These identifications with previously described species will 

 appear in their proper places in the synonymy of the various 

 birds treated of in the volume, but, from the nature of the 

 work, without note or comment. To my mind, whatever value 

 may attach to an opinion is increased at least tenfold by a 

 concise statement of the grounds upon which it is based, so 

 that the readers may be able to form an opinion of their own, 

 instead of accepting it on the authority of even the best 

 expert. Some of our most accurate writers on ornithology 

 have neglected this important point, partly perhaps from a 

 mistaken endeavour to be brief, and partly, it is to be feared, 

 from an unwillingness to commit themselves to a definite 

 line of argument, the accuracy of which might hereafter be 

 impeached. I have frequently been told, when asking for the 

 reason why an opinion in which I could not coincide was 

 expressed, that the writer had no doubt that he had excellent 

 reasons at the time for coming to the conclusions which he 

 recorded, but that now, after the lapse of some years, he was 

 not able to recall his former line of argument to memory. 

 Such replies are eminently unsatisfactory. The day in which 

 opinions were accepted solely on authority is past. Probably 

 we are in danger of rushing to the opposite extreme, and are 

 .more inclined, in those cases where the evidence does not 

 satisfy our reason, 'to give the casting vote in favour of 

 doubt. 



It appears to me that new material is so continually coming 

 forward, and old material is so frequently being raked up 

 from the nooks and corners where it has been lying hid, that 

 no ornithological opinion can be considered final, or even of 

 much value, unless accompanied by the statement of the facts 

 upon which it is based. 



In addition to the " slaughter of the innocents/' which I 

 propose to justify, to the best of my ability, in the present 

 paper there are also numerous errors of identification to 

 correct, which also require some explanation more full than 

 s consistent with the plan of the f Catalogue of Birds.' 



Acrocephalus arabicus, Heugl. Orn. N.O.-Afr. i. p. 289 



