CHARACTERS OF PAS SERES. 246 



J2 rectrices (with certain anomalous exceptions : none in P)io'epyga ; 10 in Xenicus, AcantJii- 

 sitta, Phrenotrijc, Edolius ; 16 in Menura). Tlie bill is too variable in form to furnish char- 

 acters of groups higher than families ; but its covering is always hard and horny, in part or 

 wholly — never extensively membranous, as in many wading and swimming birds, or softly 

 tumid, as in Pigeons, or cered, as in Parrots and birds of prey. The nostrils do not openly 

 communicate with each other. The oil-gland (elfeodochon, p. 89) is nude, and of a charac- 

 teristic shape. Besides these external characters, which the student may readily examine 

 without dissection, there are some more important anatomical ones. The sternum (with few 

 exceptions) is cast in a particular mould, having a forked manubrium (except Etirylcemidce), 

 prominent costal processes, and each side of the posterior border single-notched (neither entire, 

 nor deeply nor doubly notched, nor fenestrate; fig. 58). The bony palate has a peculiar 

 structure, called cegithognathous (fig. 79), but in some cases a sort of desmognathism occurs; 

 there are no basipterygoids ; the nasal bones are holorhinal. The atlas is perft)rated by the 

 odontoid process of the axis. Beddard has called attention to a disposition of the abdominal 

 septa which may be a passerine character : the oblique septa being either free from the ster- 

 num, or sharing their attachment thereto with the falciform ligament. There is but one 

 carotid artery, the left (fig. 91). Cceca coli are present, though small. The plumage is after- 

 shafted, as a rule (except Eiirylcemidce). There is a peculiarity in the method of insertion of 

 the tensor patagii brevis ; " the tendon of the muscle does not end upon the tendon of the ex- 

 tensor, as it does in the picarian bird, but, though attached to it firmly, retains its independ- 

 ence, and runs back to be attached near it to the extensor condyle of the radius" {Beddard) ; 

 there is no biceps slip, nor any expansor of the secondaries. Besides possessing the separate 

 fiexor of the hind toe already mentioned, Passeres are anomalogonatous (p. 201) — that is, the 

 ambiens is absent ; so is the accessory femorocaudal ; the femorocaudal and semitendinosus 

 are present, as is usually also the accessory semitendinosus. The formula is therefore A X Y 

 (rarely AX). 



No North American Passerine bird shows any of the exceptions noted in the foregoing 

 paragraph; all are normally passerine. 



Physiologically, the nature of Passeres is altricial and psilopfedic (p. 91); tliat is, tlie 

 young are hatched weak and naked, and require to be fed for some time in the nest by the 

 parents. They represent the highest grade of physicdogical development, as well as the most 

 perfect physical organization of the class of birds. Their nervous irritability is great, coordi- 

 nate with rapidity of respiration and circulation ; they consume the most oxygen, and live the 

 fastest, of all birds. They habitually reside above the earth, in the air that surrounds it, among 

 the plants that with them adorn it ; not on the ground, nor on " the waters under the earth." 



Pas' seres were named by Cuvier in 1798 as an order of birds; the name is simply the 

 plural of Lat. passer, a sparrow. But the group as established by him included many forms 

 which were first properly excluded by the celebrated Nitzsch, who in 1829 limited the group 

 as now accepted. Besides being one of the best defined, it is by far the largest group of its 

 grade in ornithology. For example, of the 888 birds enumerated as Nortli American in my 

 last Check List, no fewer than 894 are Passeres ; as are more than half of all known birds, or 

 about 6,000 out of some 1 1 ,500 species. 



Passeres are primarily divisible into two groups, commonly called suborders, mainly 

 according to the structure of the vocal organ — the lower larynx, or syrinx. In one of these 

 groups, the musical apparatus is highly developed, with several distinct pairs of intrinsic mus- 

 cles, inserted into the ends of the upper three half-rings t»f the bronchial tubes. In the other, 

 the voice-organ is less complex, with less specialized muscles inserted into the middle jiortions 

 of the upper bronchial half-rings. The former arrangement is termed acroiinjodian, the latter 

 mesomyodian; the two are also contrasted as polymyodian and oligomyodian, with reference to 

 number of syringeal muscles. Birds wliich exhibit this diflference of structure are respectively 



