554 



ORNITHOLOG Y 



Structure. From the author's excellent reputation as a naturalist, as 

 v ~"~v~~^well as from the specimens hitherto published, we should 

 augur that this work, on its completion, will form as valua- 

 ble a manual of British Ornithology as can be well de- 

 sired. 



Last in our list, though the reverse of lowest in our es- 

 timation, stand Mr Macgillivray's characteristic volumes, 

 the Rapacious Birds of Great Britain (1836), and the 

 History of British Birds, Indigenous and Migratory (vol. 

 1st, 1837). In regard to these two works, readers may pro- 

 bably differ in their appreciation of some insulated passages, 

 critical or otherwise, not essential to the exposition of the 

 subject in hand ; but we think all must agree that they are 

 written in a clear, vigorous, and original manner, and de- 

 void of that vapid spirit of compilation which pervades the 

 labours of so many of the ingenious author's predecessors 

 and contemporaries. 



We shall not here enter into any detailed exposition of 

 the internal structure of birds. Our space would not ad- 

 mit of our doing so in a manner likely either to satisfy our- 

 selves or to instruct our readers. The subject is of too 

 great importance to be superficially treated, and a deeper 

 scientific examination is not to be looked for here. We 

 regret to say, there is much reason to accuse the naturalist 

 of confining his attention to the external characters of liv- 

 ing beings, which, though important portions of the ani- 

 mal economy, are nevertheless only portions, though too 

 often looked upon as all in all. It is no reason for ne- 

 glecting the internal structure, that a knowledge of such 

 structure is not required to comprehend the modern sys- 

 tems. This, we must admit, is true ; but the systems are 

 thereby so much the more defective. An assured anato- 

 mical basis will never cause confusion or contrariety in 

 any good arrangement formed on the groundwork of ex- 

 ternal characters ; for the best of these are sure to conform 

 themselves with all the important modifications of internal 

 structure, while the sooner a bad arrangement is under- 

 mined the better. At the same time, that Zootomist would 

 know little of the practical importance of external forms 

 who should not endeavour to connect these with his de- 

 monstration of more recondite characters. In truth, how- 

 ever desirable it may be to know the whole of the animal 

 structure, whether external or internal, we must in rela- 

 tion to museum specimens and to zoological collections in 

 general, necessarily have recourse to superficial, or at least 

 external characters, because none other are visible, or in- 

 deed exist, in the subjects of natural history as usually 

 preserved ; and we should debar a vast multitude from a 

 most delightful study of graceful forms and gorgeous plum- 

 age, if we could learn nothing important of beast or bird 

 without prying into all the hidden wonders of its interior. 

 Whatever progress comparative anatomy may in future 

 make, we trust the Zootomist will ever bear in mind that 

 the establishment of good external characters is a matter 

 of the highest and most indispensable importance to the 

 present state and future progress of natural history, of 

 which the practical pursuit will ever mainly depend upon 

 the class of characters in question. As we cannot here 

 enter into the anatomical department of our subject, we 

 shall give, in the subjoined note, the names of a few works 

 likely to interest and instruct the reader. 1 A few para- 

 graphs will suffice for all we have ourselves to say, before 

 entering upon our systematic portion. 



The bill, composed of the upper and under mandible, 

 varies almost infinitely in its form in the different genera, 



in the determination and construction of which it affords Structure, 

 characters of tiie highest importance. As its modifications v—, "~*'— -' 

 will be specially alluded to in our notices of the minor 

 groups, and are moreover accurately represented in the 

 plates which accompany the present treatise, we need not 

 here fatigue the reader by an unnecessary enumeration. 

 A portion at the base of the upper mandible, usually con- 

 taining the nostrils, and sometimes covered with hairs or 

 feathers, sometimes partially or entirely bare, is called the 

 cere. It is very obvious in most birds of prey, but imper- 

 ceptible in many other species. When we expand the 

 mandibles, we of course perceive the opening to the ali- 

 mentary canal or digestive organs, which usually consist 

 of the following portions. 



The pharynx follows immediately after the cavity of the 

 mouth. It leads into the cesop/tagus or gullet, which in 

 many species swells into what is called the crop, by some 

 regarded as the first stomach. This is followed by a se- 

 cond enlargement, produced, however, rather by a thick- 

 ening of the coats than by any increase of capacity within, 

 named the proventriculus. It contains numerous glandular 

 sacs interposed between its muscular and mucous coats, 

 which secrete a gastric juice to aid the process of di- 

 gestion. This proventriculus leads to the gizzard or true 

 stomach, by some regarded as the third stomachic expan- 

 sion. Here the function of digestion is completed. The 

 entrance from the stomach to the small intestine is named 

 the pylorus, of which the structure is frequently valvular. 

 The first fold of the small intestine is named the duode- 

 num, and after receiving the pancreatic and biliary ducts, 

 it forms various convolutions, and terminates in the rec- 

 tum or large intestine. The cceca are usually placed at the 

 commencement of the latter ; its termination is named the 

 cloaca. 



These parts, it will be borne in mind, are variously mo- 

 dified in the different tribes. In some the expansion called 

 the crop is wanting, or not to be distinguished from the 

 other upper portions of the oesophagus ; and the powerful 

 muscles which constitute the peculiar strength, of the giz- 

 zard in granivorous birds are very feeble in the carnivo- 

 rous and fish-devouring kinds. In some the intestine is 

 long and narrow, in others short and wide, while the caeca 

 exhibit a corresponding range, being in certain kinds ex- 

 tremely long, in others merely rudimentary. 



Birds are remarkable for the energy of their respiratory 

 functions. Although their lungs are rather small, they 

 are perforated in such a way as to communicate with mem- 

 branous cells distributed through various parts of the body, 

 and even communicating with the interior of the bones, so 

 that the atmospheric air not only conies in contact with 

 the pulmonary vessels, but with a great proportion of the 

 circulating system. Thus birds have been said to respire 

 by the branches of the aorta, as well as by those of the 

 pulmonary artery. It is thus that the most rapid exercise 

 of the faculty of flight impairs not their power of breath- 

 ing ; and the best-trained hunter that ever bounded re- 

 joicingly over the fences of Leicestershire is far sooner 

 blown than a field sparrow. 



The trachea or windpipe is composed of bony rings. 

 The upper larynx is of comparatively simple structure, 

 and of less importance than among the mammiferous class; 

 but farther down, and close upon the bifurcation of the 

 trachea, is the lower larynx, the true organ of the voice in 

 birds. The vast bulk of air contained in the interior cells 

 no doubt contributes to the strength of their vocal powers, 

 while the muscles of the inferior portion of the larynx, and 



1 Cuvier's Legons d'Anatomie Comparle ; Carus's Introduction to Comparative Anatomy, translated from the German by Mr Gore 

 (there is a better and more recent French edition of this work) ; Meckel's Traiii General d'Anatomie ComparCe ; Grant's Outlines of 

 Comparative Anatomy ; Mr Owen's article Aves, in Todd's Cyclopaedia of Anatomy and Physiology ; and the Introduction to Macgillivray's 

 History of British Birds, vol. i. 



