2 DENDROCOLAVTlD-i:. 



rcplaceil by a tendinous strap. The memhrana tj/nqxtniformis passes 

 over from one bronchus to the otlier. The bronchi contain half-rings 

 only. The membranous wall of the voice-organ consists of two thin 

 transparent membranes, of which the inner one is the mucous 

 membrane." * 



The forms that possess this abuormal structure of the voice-organs, 

 so far as they are at present known to us, are entirely confined to 

 the Xeotropical Eegion. 



Scheme of Tracheophonine Fasseres. 



Four families of the Tracheophonine Passeres are now generally 

 recognized, which, after separating the two families with abnormal 

 formation of the sternum, may be shortly distinguished, as shown by 

 Sundevall (' Method! Xaturalis avium disponendarum Tentamen'), 

 by the structure of their tarsal scutes. 



A. Sternum with one pair of posterior 



notches. 



a. Tarsus endaspidean 1. TendrocolaptidSB, p. 2. 



b. Tarsus taxaspidean 2. Forinicariidae, p. 176. 



B. Sternum with two pairs of posterior 



notches. 



c. Tarsus exaspidean 3. Conopophagidse t, p. 329. 



d. Tarsus taxaspidean 4. Pteroptochidae, p. 337. 



Family I. DENDROCOLAPTID.^. 



As green in various shades is the usual colour of the Tyranmchv, 

 so brown of different tints is the prevailing colour of the great Neo- 

 tropical family DendrocoJaptidce, and in a large proportion of the 

 species it will be found that the tail is of a uniform chestnut or fer- 

 ruginous. All the Demlrocolaptidce are of small, or, at anj* rate, of 

 moderate size, the largest of them being perhaps the members of the 

 genus Xiphocolaptes, which, however, do not much exceed 10 inches 

 in length of body, and the smallest being found among the Synal- 

 la.i'incr. Though doubtless of one original stock, these birds have 

 arrived, after long ages of slight variations, at verj' various states of 

 external structure and corresponding habits. In their spiny tails 

 and sharpened claws the typical Dendrocolaptince have assumed the 

 outward character of the Tree-Creepers (Certhia), and pass their 

 lives much in the same way, clasped to the holes and branches of 

 the larger trees, where they seek their food. The Oven-birds and 

 their allies have diverged in another direction, and are eminently 



* See ' Ueber die bisher unbekannten typisehen Verschiedenheiten der Stimm- 

 organe der Passeriiien,' von J. Miiller. Berlin, 1847. 

 r Cf. Forbps, P. Z. S. 1881 , p. 435. 



