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Show 6 PROF. w. LILLJEBORG O N T H E CLASS O F BIRDS. [Jan. 9, The new genera and species that had been added since Latham's ' Index Ornithologicus' was edited had increased to such a number, and their literature had become so scattered, that such a work as G. R. Gray's systematic 'List of the Genera of Birds,' although only a list of names without characters, was very necessary to science, and the obtaining of the same also highly beneficial. The right of priority has generally been observed in this work. The same author has, in his ' Genera of Birds,' given descriptions of the orders, families, and genera, and even figures of the same. A single species of some genera is represented by a coloured figure; and of others only certain parts, such as the head or the foot of some typical species, have been figured. This work is certainly of great value for the study of birds; and the very good figures often give a necessary explanation to the descriptions of the genera, which at times are but little distinguishable, and are not given in a diagnostic manner. Cabanis has, in his ornithological system, given good characters for the arranged groups, taken partly from J. Miiller's descriptions of the larynx inferior, partly from the nature of the horny covering on the tarsi, first studied by Keyersling and Blasius, and partly from the number of quills and tail-feathers. It is principally the order Pas-seres to which this author has devoted his attention, and which consequently has obtained an improved classification. It has been divided into two groups (Oscines and Clamatores), and the families have been carefully limited and arranged. This work, with that of Sundevall, may rightly be considered most important in the classification of birds. The numerous contributions to this classification that have been made by Bonaparte are valuable as giving minute registers of families and species, showing an unusual knowledge of the species, and a sharp distinction between the genera, and often arranging these in a manner corresponding with the demands of the natural affinity; but they are generally only registers of names, often giving the characters for the species, but very seldom for the higher groups. Bonaparte has published, in the ' Transactions of the Linnean Society,' xviii. p. 258, a systematic arrangement of the class of birds, together with the classes of the other vertebrated animals in general. The first class has been divided into two subclasses-Insessores and Grallatores. The first of these corresponds fully with the one arranged by us under the same name, and the latter includes both Grallse and Natatores. This classification corresponds also with the one given here, in the Longipennes having their place between the Steganopodes and the Pygopodes. Characters of the orders, families, and subfamilies are also given. After this brief reference to the literature, we will proceed to a synoptic statement of the principles upon which the systematic arrangement here given rests. Principles.-We have preferred the progressive method, as it seems to us to be the most rational, from its correspondence with the physiological and geological development. W e therefore commence the system with the lowest, and finish it with the highest forms. |
