+Rhea darwini+, _Darwin, Zool. Voy. 'Beagle,'_ iii. p. 123, pl. xlvii.; _Hudson, P. Z. S._ 1872, p. 534; _Sclater, Trans. Zool. Soc._ iv. p. 357, pl. lxx.; _Gadow, P. Z. S._ 1885, p. 308. +Pterocnemis darwini+, _Scl. et Salv. Nomencl._ p. 154. _Description._--Above red or buff-brown, most of the feathers of the back with white shaft-stripes and wide white margins: beneath, throat and neck buff-brown; rest of under surface whitish; front of tarsus covered on the upper part by small reticulate scutes, on the lower part by transverse scutes: whole length about 36·0 inches, tarsus 11·0; tarsus partly feathered. [Illustration: Head of _Rhea darwini_. (P. Z. S. 1860, p. 209.)] _Hab._ Patagonia south of the Rio Negro. Darwin's Rhea inhabits Patagonia from the Straits of Magellan to the Rio Negro, and is also met with occasionally north of that river. The Indians call it "Molú Chueké"--short or dwarf Chueké; its Spanish name is "_Avestruz petizo_." They were formerly very abundant along the Rio Negro; unhappily, some years ago their feathers commanded a very high price; Gauchos and Indians found that hunting the Ostrich was their most lucrative employment; consequently these noble birds were slaughtered in such numbers that they have been almost exterminated wherever the nature of the country admits of their being chased. When on the Rio Negro in 1871 I was so anxious to obtain specimens of this Rhea that I engaged several Indians by the offer of a liberal reward to hunt for me, but they failed to capture a single adult bird. I can only set down here the most interesting facts I was able to collect concerning its habits, which are very imperfectly known.