7^ DICTIONARY OF BIRDS 



divided fhe Class Aves into two Subclasses, to which he applied the names 

 of Insessores and Grallatores (hitherto used by their inventors Vigors and 

 Illiger in a different sense), in the latter work relying chiefly for this 

 division on characters which had not before been used by any systematist, 

 namely, that in the former group Monogamy generally prevailed and the 

 helpless nestlings were fed by their parents, while the latter group were 

 mostly Polygamous, and the chicks at birth were active and capable of 

 feeding themselves. This method, which in process of time was dignified 

 by the title of a Physiological Arrangement, was insisted upon with more 

 or less pertinacity by the author throughout a long series of publications, 

 some of them separate books, some of them contributed to the memoirs 

 issued by many scientific bodies of various European countries, ceasing only 

 at his death, which in July 1857 found him occupied upon the unfinished 

 Conspectus Generum Avium before mentioned. In the course of this series, 

 however, he saw fit to alter the name of his two Subclasses, since those 

 which he at first adopted were open to a variety of meanings, and in a 

 communication to the French Academy of Sciences in 1853 (Gomptes 

 Bendus, xxxvii. pp. 641-647) the denomination Insessores was changed to 

 Altrices, and Grallatores to Preecoces — -the terms now preferred by him 

 being taken from Sundevall's treatise of 1835 already mentioned. The 

 views of Bonaparte were, it appears, also shared by an ornithological 

 amateur of some distinction, Hogg, who propounded a scheme which, as 

 he subsequently stated {Zool. 1850, p. 2797), was founded strictly in 

 accordance with them ; but it would seem that, allowing his convictions 

 to be warped by other considerations, he abandoned the original 

 "physiological" basis of his system, so that this, when published in 1846 

 {Edinh. N. Philos. Journ. xli. pp. 50-71) was found to be established on a 

 single character of the feet only, whereon he defined his Subclasses Con- 

 strictipedes and Inconstridipedes. The numerous errors made in his asser- 

 tion hardly need pointing out. Yet the idea of a " physiological " arrange- 

 ment on the same kind of principle found another follower, or, as he thought, 

 inventor, in Newman, who published (Proc. Zool. Soc. 1850, pp. 46-48, 

 and Zool. pp. 2780-2782) a plan based on exactly the same considerations, 

 dividing Birds into two groups, "'Hesthogenous " — a word so vicious in 

 formation as to be incapable of amendment, but intended to signify those 

 that were hatched with a clothing of down — and " Gymnogenous," or 

 those that were hatched naked. These three systems are essentially 

 identical ; but, plausible as they may be at the first aspect, they have 

 been found to be practically useless, though such of their characters as their 

 upholders have advanced with truth deserve attention, and, as will be seen 

 in the present work, Dr. Gadow's terms Nidicolx and Nidifugx, used in no 

 systematic sense, express with greater accuracy what is needed. Physiology 

 may one day very likely assist the systematist ; but it must be real 

 physiology and not a sham. 



In 1856 Prof. Gervais, who had already contributed to the Zoologie 

 of M. de Castelnau's Expedition dans les parties centrales de VAmerique du 

 Sud some important memoirs describing the anatomy of the Hoactzin 

 (page 421) and certain other Birds of doubtful or anomalous position, 

 published some remarks on the characters which could be drawn from the 



