246 



S YS TEMA TIC S YNOPSIS. — PA SSERES — OSCINES. 



called Passeres acromyodi and Passeres mesomyodi, or Oscines and Clamatores.^ (See p. 212, 

 fig. 101.) 



Associated with the acromyodian or oscine type of syrinx is a peculiar condition of the 

 tarsal envelop. In nearly all Oscines, the tarsus is covered on each side with a horny plate, 

 nearly or quite undivided, meeting its fellow in a sharp ridge behind. This condition of the 

 tarsus is called bilaminate, and birds showing it are laminiplantar (tigs. 37, 42, 43). In some 

 cases fusion of the tarsal envelop proceeds so far that the front of the tarsus likewise presents 

 a nearly or quite undivided surface, the whole tarsus being then encased in a " boot," as it is 

 called. A " booted " tarsus may be said to be trilaminate (fig. 36). The principal exception 

 to association of a bilaminate or trilaminate tarsus with an acromyodian syrinx is afforded by 

 Alaudida, which have the tarsus scutellate and blunt behind; and, with very few exceptions, 

 no bird which is not acromyodian has a bilaminate tarsus. A third important feature charac- 

 terizes Oscines, as a rule. This is reduction in length of the 1st primary, which never equals 

 the longest primary in length, is rarely over f as long as tlie longest, is so short as to be called 

 spurious, or is quite rudimentary and apparently wanting, leaving apparently only 9 primaries 

 (fig. 30). 



Associated with the mesomyodian or clamatorial type of syrinx is seen (with few excep- 

 tions) an opposite condition of the tarsus, the sides and back of which, as well as the front, 

 are covered with variously arranged scutella, so that there is no sharp undivided ridge behind. 

 In such cases there are also 10 fully developed primaries, the 1st of which, if not equalling or 

 being itself the longest, is at least f as long. (See p. 510, fig. 343.) 



These combinations of characters may be contrasted for the purpose of dividing the great 

 group Passeres into two sections, conventionally denominated suborders. 



1 . Suborder ACROMYODI, POLYMYODI, OR OSCINES : Singing Birds. 



Syrinx with 4 or 5 distinct pairs of intrinsic muscles, inserted at ends of 3 upper bronchial 

 ^ half-rings, and thus constituting a highly complex and 



effective musical apparatus. Each side of tarsus cov- 

 ered with a horny plate meeting its fellow in a sharp 

 ridge behind; front of tarsus also sometimes laminate. 

 Primaries apparently 10, the 1st short or spurious; or 

 apparently only 9. 



Here belong all the North American families of 

 ji^ Passeres, except Tyrannidcc, or Flycatchers, and 

 Cotingidce, which are clamatorial (mesomyodian). 

 The only North American exceptions to the diagnosis 

 given are afforded by Alaudidre, or Larks, and cer- 

 tain Troglodytince, which, with an oscine syrinx and 



wins-structure, do not havt 



bilaminate tarsus. "■^ 



Of our nearly 550 Passerine species and subspecies, 

 no fewer than ,500 are Oscine. The name is the 

 Lat. os'ceu, n. pi. os'cines, divining-birds — those 

 whose notes were regarded as augural. 

 It is a question, which one of tlie numerous Oscine families should be placed at the head 



Fig. 113. — Thrushes : European Redwing 

 [Turdus iliacus) and Fieldfare (T. pilaris). 

 From Dixon. 



1 I do not wish to modify this statement, made in former editions of the Key, notwithstanding what is said of 

 Eurylwmidoe in the note on p. 244. 



- The most abnormal Oscines are the Australian Scrub-birds and Lyre-birds, Atrichiida and Meimrid(B. In these 

 the syringeal muscles are reduced, the furculum is rudimentary, there are more than the typical number of rectrices, 

 etc. — so that these families are sometimes made a prime division, Pseiidoseines or Abnormales, contrasted with 

 Normales. 



