VTEROPTOCHID^. 337 



Family IV, PTEROPTOCHID.E*. 



The peculiar and limited group which, after its oldest established 

 genus, is now generally denominated Pteroptocliidce, forms a small 

 but well-marked family of Tracheophouinc Passeres, mostly restricted 

 to Chili and the south-western portions of the South-American 

 continent, but also represented in the Andes of Peru, Ecuador, and 

 Colombia, and in the higher elevations of Brazil. They are ground- 

 birds, remarkable externally for their large and robust feet, with 

 long claws, and their strangely formed bills, in which the nosti'ils 

 are more or less covered by a membrane ; and internally for the 

 singular form of the syrinx and the double-notched sternum. They 

 are Wren-like in general appearance, and carry the tail in an 

 elevated iDosition. 



Key to the Genera. 



A. Mesorliiuium compressed, rounded, elon- 



gated. 

 «. Bill thin, subulate. 



a'. Tail short ; loral plumes short .... 1. Scytalopus, p. 337. 

 h'. Tail loug; loral plumes elongated. . 2. Merulaxis, p. 343. 

 h. Bill strong, thick. 



c'. Tarsal scales obsolete ; culmen 



straight 3. Liosceles, p. 344. 



d'. Tarsal scutes divided ; culmen 

 incurved, 

 a". Hinder claw short. 



J Bill longer 4. Pteroptochus, p. 345. 



I Bill shorter 5. Rhixocrypta, p. 347. 



h". Hinder claw long, incurved .... 6. Hylactes, p. 348. 



B. Mesorhinium expanded into an oval 



shield. 



c. Hinder claw long, sti-aight, sharp .... 7. Acroptehnis, p. 350. 



d. Hinder claw moderate, curved 8. TriptobhintjS, p. 351. 



1. SCYTALOPUSt. 



Type. 



Scytalopus, Gould, P. Z. S. 183G, p. 89 S. magellanicus. 



Sylviaxis, Less. Per. Zool. 1840, p. 274 S. magellanicus. 



Agathopus, Scl. P. Z. S. 1858, p. C9 S. analis. 



* See my paper on this family, Ibis, 1S74, p. 189. 

 t Eefer also to : — 



(1) S)/Iviaxis gutfafus, Less. Eev. Zool. 1840, p. 274. 



(2) Scytalojms feimndis, Tscli. Faun. Per., Av. p. 182. 

 (.3) S. acutirostris, Tsch. op. cit. p. 183. 



(4) S. boUvianuf, Allen, Bull. A. M. N. H. ii. p. 98 (Bolivia). 



VOL. XV. 



