28 



ORNITHOLOGY 



he also examined ; and he practically, though not literally, 1 

 asserted the truth, when he said that the general struc- 

 ture, but especially the muscular appendages, of the lower 

 larynx was " similarly formed in all other birds of this 

 family" described in Audubon's work. Macgillivray did 

 not, however, assign to this essential difference any 

 systematic value. Indeed he was so much prepossessed 

 in favour of a classification based on the structure of the 

 digestive organs that he could not bring himself to con- 

 sider vocal muscles to be of much taxonomic use, and it 

 Johannes was reserved to Johannes Muller to point out that the 

 Mailer. con trary was the fact. This the great German compara- 

 tive anatomist did in two communications to the Academy 

 of Sciences of Berlin, one on the 26th June 1845 and the 

 other on the 14th May 1846, which, having been first 

 briefly published in the Academy's Monatsbericht, were 

 afterwards printed in full, and illustrated by numerous 

 figures, in its Abhandlungen, though in this latter and 

 complete form they did not appear in public until 1 847. 

 This very remarkable treatise forms the groundwork of 

 almost all later or recent researches in the comparative 

 anatomy and consequent arrangement of the Passeres, and, 

 though it is certainly not free from imperfections, many of 

 them, it must be said, arise from want of material, not- 

 withstanding that its author had command of a much 

 more abundant supply than was at the disposal of Nitzsch. 

 Carrying on the work from the anatomical point at which 

 lie had left it, correcting his errors, and utilizing to the 

 fullest extent the observations of Keyserling and Blasius, 

 to which reference has already been made, Muller, though 

 hampered by mistaken notions of which he seems to have 

 been unable to rid himself, propounded a scheme for the 

 classification of this group, the general truth of which has 

 been admitted by all his successors, based, as the title of 

 his treatise expressed, on the hitherto unknown different 

 types of the vocal organs in the Passerines. He freely 

 recognized the prior discoveries of, as he thought, 

 Audubon, though really, as has since been ascertained, of 

 Macgillivray ; but Muller was able to perceive their system- 

 atic value, which Macgillivray did not, and taught others 

 to know it. At the same time Muller shewed himself, his 

 power of discrimination notwithstanding, to fall behind 

 Nitzsch in one very crucial point, for he refused to the 

 latter's Picarise the rank that had been claimed for them, 

 and imagined that the groups associated under that name 

 formed but a third " Tribe " — Picarii — of a great Order 

 Insessores, the others being (1) the Oscines or Polymyodi 

 — the Singing Birds by emphasis, whose inferior larynx 

 was endowed with the full number of five pairs of song- 

 muscles, and (2) the Tracheophones, composed of some 

 South-American Families. Looking on Midler's labours 

 as we now can, we see that such errors as he committed 

 are chiefly due to his want of special knowledge of 

 Ornithology, combined with the absence in several 

 instances of sufficient materials for investigation. Nothing 

 whatever is to be said against the composition of his first 

 and second " Tribes " ; but the third is an assemblage still 

 more heterogeneous than that which Nitzsch brought 

 together under a name so like that of Muller — for the 

 fact must never be allowed to go out of sight that the 

 extent of the Picarii of the latter is not at all that of the 

 Picarise of the former. 2 For instance, Muller places in his 



1 Not literally, because a few other forms such as the genera Polio- 

 ptila and PlUogonys, now known 1" have ii" relation to the Tyrannidse, 

 ... i. included, though these forms, it would seem, had never been dis- 

 sected by him. On the other hand he declares that the American 

 Redstart, Muscieapa, or, as it now stands, X /< ■/ -A . iga ruticilla, when 

 young, has its vocal organs like the rest — an extraordinary statemenl 

 which is worthy the attention of the many able American ornitl 



• It is not needless to point out tins line distinction, for more than 

 one modern author would seem to have overlooked it. 



third " Tribe " the group which he called Ampelidse, mean- 

 ing thereby the peculiar forms of South America that are 

 now considered to be more properly named Cotingidse, and 

 herein he was clearly right, while Nitzsch, who (mislei I 1 ly 

 their supposed affinity to the genus Ampelis — peculiar to 

 the Northern Hemisphere, and a purely Passerine form) 

 had kept them among his Passerines, was as clearly wrong. 

 But again Muller made his third "Tribe" Picarii also to 

 contain the Tyrannidse, of which mention has just been 

 made, though it is so obvious as now to be generally 

 admitted that they have no very intimate relationship to 

 the other Families with which they are there associated. 

 There is no need here to criticize more minutely his pro- 

 jected arrangement, and it must be said that, notwithstand- 

 ing his researches, he seems to have had some misgivings 

 that, after all, the separation of the Insessores into those 

 " Tribes " might not be justifiable. At any rate he wavered 

 in his estimate of their taxonomic value, for he gave an 

 alternative proposal, arranging all the genera in a single 

 series, a proceeding in those days thought not only defens- 

 ible and possible, but desirable or even requisite, though 

 now utterly abandoned. Just as Nitzsch had laboured 

 under the disadvantage of never having any example of 

 the abnormal Passeres of the New World to dissect, and 

 therefore was wholly ignorant of their abnormality, so 

 Midler never succeeded in getting hold of an example of 

 the genus Pitta for the same purpose, and yet, acting on 

 the clew furnished by Keyserling and Blasius, he did not 

 hesitate to predict that it would be found to fill one of 

 the gaps he had to leave, and this to some extent it has 

 been since proved to do. 



The result of all this is that the Oscines or true Passeres are 

 found to be a group in which the vocal organs not only attain the 

 greatest perfection, but are nearly if not quite as uniform in their 

 structure as is the sternal apparatus ; while at the same time each 

 set of characters is wholly unlike that which exists in any other 

 group of Birds. In nearly all Birds the inferior larynx, or syrinx, 

 which is, as proved long ago by the experiments of Cuvier, the seat 

 of their vocal powers, is at the bottom of the trachea or windpipe, 

 and is formed by the more or less firm union of several of the bony 

 rings of which that tube is composed. In the Ratitse, the genus 

 Shea excepted, ami in one group of Carinatx, the American 

 Vultures Cathartidse, but therein it is believed only, there is no 

 special modification of the trachea into a syrinx ; 3 but usually, at 

 a little distance from the lungs, the trachea is somewhat enlarged, 

 and here is found a thicker and stouter bony ring, which is bisected 

 axially by a septum or partition extending from behind forwards, 

 and thus dividing the pipe, 4 each half of which swells out below the 

 ring and then rapidly contracts to enter the lung on its own side. 

 The halves of the pipe thus formed are the bronchi, tubes whose 

 inner side is flattened and composed of the memhrana tympani- 

 formis, on the change of form and length of which some of the 

 varieties of intonation depend, while the outer and curved side is 

 supported by bony half-hoops, connected by membrane just as are 

 the entire hoops of the upper part of the trachea. The wholo of 

 this apparatus is extremely flexible, and is controlled by muscles, 

 the real vocal muscles of which mention has previously been so 

 frequently made. These vary in number in different groups of 

 Birds, and reach their maximum in the Oscines, which have always 

 live pairs, or even more according to some authorities. 5 But sup- 

 posing five to be the number of pairs, as it is generally allowed to 

 be in this group of them, two pairs have a common origin about 

 the middle of the trachea, and, descending on its outside, divide at 

 a short distance above the lower end of the tube ; one of them, the 

 tensor posterior longus, being directed downward and backward, is 

 inserted at the extreme posterior end of the first half-ring of the 

 bronchus, while its counterpart, the tensor anterior longus, passing 

 from the place of separation downward and forward, is inserted 

 below the extreme point of the last ring of the trachea. Within 

 the angle formed by the divergence of each of these pairs of 

 muscles, a third slender muscle — the sterno-traehealis— is given oil' 



3 See Bums, vol. in. p. 720 ; but </. Forbes, Proc. Zool. Society, 

 1881, pp. 778, 788. 



4 In a few forms belonging to the Spheniscidm and ProceUariidse, 

 this septum is prolonged upwards, to what purpose is of course 

 unknown. On the other hand, the Parrots have no septum (see Bikds, 

 i 



5 See Bikds, vol. iii. p. 726. 



