ON THE PROGRESS AND PRESENT STATE OF ORNITHOLOGY. 179 



History,' vols. vi. vii. viii. Some critiques on the second edition were also 

 made in the ' Revue Zoologique,' 1842, by Dr. Hartlaub, a skilful ornitholo- 

 gist of Bremen, who is understood to be preparing a general work on orni- 

 thology, including the distinctive characters of the species. 



Mr. G. R. Gray is now engaged in issuing the 'Genera of Birds' in a 

 much more complete and extMided form, including the essential characters 

 of the various groups, and full lists of the species and their synonyms. In 

 this work he endeavours to reduce the various genera to an equality of I'ank, 

 and is consequently compelled to reunite such genera as appear to have been 

 separated by other authors on insufficient grounds. This task requires much 

 judgement as well as industry, but with the resources which the galleries of 

 the British Museum supply to Mr. Gray, he has been enabled to execute it 

 with great success. The lithographic plates which accompany the work 

 exhibit the essential characters of every genus, and of a large number of new 

 or rare species, and the admirable mode in which they are executed by Mr. 

 D. W. Mitchell confers a high degree of excellence upon this publication. 



I may here be allowed to mention an undertaking of my own which has 

 occupied the leisure of several years, but which is not yet sufficiently matured 

 for publication, — a complete Synonymy of all known species of birds, with 

 full references to all the works where they are figured or described. This 

 undertaking requires considerable labour and much careful comparison of 

 specific character, as exhibited both in nature and in books, but there is 

 probably no department of natural history in which, from the multiplication 

 of nominal species, and the wide dispersion of the materials, such an analysis 

 of the whole subject is more wanted than in ornithology. 



Works of reference connected with ornithology, though not strictly syste- 

 matic, may be briefly mentioned here. The ' Dictionnaire des Sciences Na- 

 turelles,' the ' Dictionnaire Nouveau d'Histoire Naturelle,* the ' Encyclopedic 

 Methodique,' and the ' Dictionnaire Classique d'Histoire Naturelle,' were all 

 useful works, though now more or less superseded by the progress of science. 

 The best and most recent work 'of the kind is the ' Dictionnaire Universel 

 d'Histoire Naturelle,' now publishing at Paris, and edited by M. C.D'Orbigny. 

 The ornithological articles have been, till recently, written by M. de La- 

 fresnaye, whose name is a sufficient guarantee for their accuracy. The illus- 

 trative plates are engraved with care, but in a stiff and mechanical style, and 

 the colouring is frequently too vivid. Our own country has been less pro- 

 lific in dictionaries of natural history than France, but zoological subjects 

 are adequately treated of in more comprehensive works of reference, such as 

 the ' Encyclopaedia Britannica,' and ' Metropolitana,' and the excellent 'Penny 

 Cyclopsedia,' in which the ornithological articles are very carefully compiled. 

 The same remark applies to the 'AUgemeine Encyclopadie,' published at 

 Leipzig by Ersch and Gruber. 



An indispensable index to ornithology, as indeed to every other branch of 

 natural history, is the ' Nomenclator Zoologicus' of Professor Agassiz, 

 which is a list of all the names of groups, with references to the works where 

 they were first proposed. The portion relating to birds has undergone care- 

 ful revision, and is believed to present a near approach to accuracy. 



While speaking of general methods of classification I may refer to a new 

 and unlooked-for source, from which a reflected light may in some cases be 

 thrown upon doubtful points of ornithic affinity. The parasitic insects of 

 the order Anoplura which abound on almost every species of bird, have been 

 till recently most unduly neglected, but that able entomologist Mr. Denny 

 has lately taken up this branch of zoology, and after publishing, with the aid 

 of the British Association, a beautiful work on British Anoplura, is now oc- 



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